Documentation

Overview

Package firestore provides a client for reading and writing to a Cloud Firestore database.

See https://cloud.google.com/firestore/docs for an introduction to Cloud Firestore and additional help on using the Firestore API.

See https://godoc.org/cloud.google.com/go for authentication, timeouts, connection pooling and similar aspects of this package.

Note: you can't use both Cloud Firestore and Cloud Datastore in the same project.

Creating a Client

To start working with this package, create a client with a project ID:

ctx := context.Background()
client, err := firestore.NewClient(ctx, "projectID")
if err != nil {
	// TODO: Handle error.
}

CollectionRefs and DocumentRefs

In Firestore, documents are sets of key-value pairs, and collections are groups of documents. A Firestore database consists of a hierarchy of alternating collections and documents, referred to by slash-separated paths like "States/California/Cities/SanFrancisco".

This client is built around references to collections and documents. CollectionRefs and DocumentRefs are lightweight values that refer to the corresponding database entities. Creating a ref does not involve any network traffic.

states := client.Collection("States")
ny := states.Doc("NewYork")
// Or, in a single call:
ny = client.Doc("States/NewYork")

Reading

Use DocumentRef.Get to read a document. The result is a DocumentSnapshot. Call its Data method to obtain the entire document contents as a map.

docsnap, err := ny.Get(ctx)
if err != nil {
	// TODO: Handle error.
}
dataMap := docsnap.Data()
fmt.Println(dataMap)

You can also obtain a single field with DataAt, or extract the data into a struct with DataTo. With the type definition

type State struct {
	Capital    string  `firestore:"capital"`
	Population float64 `firestore:"pop"` // in millions
}

we can extract the document's data into a value of type State:

var nyData State
if err := docsnap.DataTo(&nyData); err != nil {
	// TODO: Handle error.
}

Note that this client supports struct tags beginning with "firestore:" that work like the tags of the encoding/json package, letting you rename fields, ignore them, or omit their values when empty.

To retrieve multiple documents from their references in a single call, use Client.GetAll.

docsnaps, err := client.GetAll(ctx, []*firestore.DocumentRef{
	states.Doc("Wisconsin"), states.Doc("Ohio"),
})
if err != nil {
	// TODO: Handle error.
}
for _, ds := range docsnaps {
	_ = ds // TODO: Use ds.
}

Writing

For writing individual documents, use the methods on DocumentReference. Create creates a new document.

wr, err := ny.Create(ctx, State{
	Capital:    "Albany",
	Population: 19.8,
})
if err != nil {
	// TODO: Handle error.
}
fmt.Println(wr)

The first return value is a WriteResult, which contains the time at which the document was updated.

Create fails if the document exists. Another method, Set, either replaces an existing document or creates a new one.

ca := states.Doc("California")
_, err = ca.Set(ctx, State{
	Capital:    "Sacramento",
	Population: 39.14,
})

To update some fields of an existing document, use Update. It takes a list of paths to update and their corresponding values.

_, err = ca.Update(ctx, []firestore.Update{{Path: "capital", Value: "Sacramento"}})

Use DocumentRef.Delete to delete a document.

_, err = ny.Delete(ctx)

Preconditions

You can condition Deletes or Updates on when a document was last changed. Specify these preconditions as an option to a Delete or Update method. The check and the write happen atomically with a single RPC.

docsnap, err = ca.Get(ctx)
if err != nil {
	// TODO: Handle error.
}
_, err = ca.Update(ctx,
	[]firestore.Update{{Path: "capital", Value: "Sacramento"}},
	firestore.LastUpdateTime(docsnap.UpdateTime))

Here we update a doc only if it hasn't changed since we read it. You could also do this with a transaction.

To perform multiple writes at once, use a WriteBatch. Its methods chain for convenience.

WriteBatch.Commit sends the collected writes to the server, where they happen atomically.

writeResults, err := client.Batch().
	Create(ny, State{Capital: "Albany"}).
	Update(ca, []firestore.Update{{Path: "capital", Value: "Sacramento"}}).
	Delete(client.Doc("States/WestDakota")).
	Commit(ctx)

Queries

You can use SQL to select documents from a collection. Begin with the collection, and build up a query using Select, Where and other methods of Query.

q := states.Where("pop", ">", 10).OrderBy("pop", firestore.Desc)

Supported operators include '<', '<=', '>', '>=', '==', 'in', 'array-contains', and 'array-contains-any'.

Call the Query's Documents method to get an iterator, and use it like the other Google Cloud Client iterators.

iter := q.Documents(ctx)
defer iter.Stop()
for {
	doc, err := iter.Next()
	if err == iterator.Done {
		break
	}
	if err != nil {
		// TODO: Handle error.
	}
	fmt.Println(doc.Data())
}

To get all the documents in a collection, you can use the collection itself as a query.

iter = client.Collection("States").Documents(ctx)

Transactions

Use a transaction to execute reads and writes atomically. All reads must happen before any writes. Transaction creation, commit, rollback and retry are handled for you by the Client.RunTransaction method; just provide a function and use the read and write methods of the Transaction passed to it.

ny := client.Doc("States/NewYork")
err := client.RunTransaction(ctx, func(ctx context.Context, tx *firestore.Transaction) error {
	doc, err := tx.Get(ny) // tx.Get, NOT ny.Get!
	if err != nil {
		return err
	}
	pop, err := doc.DataAt("pop")
	if err != nil {
		return err
	}
	return tx.Update(ny, []firestore.Update{{Path: "pop", Value: pop.(float64) + 0.2}})
})
if err != nil {
	// TODO: Handle error.
}

Google Cloud Firestore Emulator

This package supports the Cloud Firestore emulator, which is useful for testing and development. Environment variables are used to indicate that Firestore traffic should be directed to the emulator instead of the production Firestore service.

To install and run the emulator and its environment variables, see the documentation at https://cloud.google.com/sdk/gcloud/reference/beta/emulators/firestore/. Once the emulator is running, set FIRESTORE_EMULATOR_HOST to the API endpoint.

Index

Examples

Constants

View Source
const (
	// Delete is used as a value in a call to Update or Set with merge to indicate
	// that the corresponding key should be deleted.
	Delete sentinel = iota

	// ServerTimestamp is used as a value in a call to Update to indicate that the
	// key's value should be set to the time at which the server processed
	// the request.
	//
	// ServerTimestamp must be the value of a field directly; it cannot appear in
	// array or struct values, or in any value that is itself inside an array or
	// struct.
	ServerTimestamp
)
View Source
const DefaultTransactionMaxAttempts = 5

    DefaultTransactionMaxAttempts is the default number of times to attempt a transaction.

    View Source
    const DetectProjectID = "*detect-project-id*"

      DetectProjectID is a sentinel value that instructs NewClient to detect the project ID. It is given in place of the projectID argument. NewClient will use the project ID from the given credentials or the default credentials (https://developers.google.com/accounts/docs/application-default-credentials) if no credentials were provided. When providing credentials, not all options will allow NewClient to extract the project ID. Specifically a JWT does not have the project ID encoded.

      View Source
      const DocumentID = "__name__"

        DocumentID is the special field name representing the ID of a document in queries.

        Variables

        View Source
        var LogWatchStreams = false

          LogWatchStreams controls whether watch stream status changes are logged. This feature is EXPERIMENTAL and may disappear at any time.

          View Source
          var ReadOnly = ro{}

            ReadOnly is a TransactionOption that makes the transaction read-only. Read-only transactions cannot issue write operations, but are more efficient.

            Functions

            func ArrayRemove

            func ArrayRemove(elems ...interface{}) arrayRemove

              ArrayRemove specifies elements to be removed from whatever array already exists in the server.

              If a value exists and it's an array, values are removed from it. All duplicate values are removed. If a value exists and it's not an array, the value is replaced by an empty array. If a value does not exist, an empty array is created.

              ArrayRemove must be the value of a field directly; it cannot appear in array or struct values, or in any value that is itself inside an array or struct.

              Example (Update)
              Output:
              
              

              func ArrayUnion

              func ArrayUnion(elems ...interface{}) arrayUnion

                ArrayUnion specifies elements to be added to whatever array already exists in the server, or to create an array if no value exists.

                If a value exists and it's an array, values are appended to it. Any duplicate value is ignored. If a value exists and it's not an array, the value is replaced by an array of the values in the ArrayUnion. If a value does not exist, an array of the values in the ArrayUnion is created.

                ArrayUnion must be the value of a field directly; it cannot appear in array or struct values, or in any value that is itself inside an array or struct.

                Example (Create)
                Output:
                
                
                Example (Update)
                Output:
                
                

                func FieldTransformIncrement

                func FieldTransformIncrement(n interface{}) transform

                  FieldTransformIncrement returns a special value that can be used with Set, Create, or Update that tells the server to transform the field's current value by the given value.

                  The supported values are:

                  int, int8, int16, int32, int64
                  uint8, uint16, uint32
                  float32, float64
                  

                  If the field does not yet exist, the transformation will set the field to the given value.

                  func FieldTransformMaximum

                  func FieldTransformMaximum(n interface{}) transform

                    FieldTransformMaximum returns a special value that can be used with Set, Create, or Update that tells the server to set the field to the maximum of the field's current value and the given value.

                    The supported values are:

                    int, int8, int16, int32, int64
                    uint8, uint16, uint32
                    float32, float64
                    

                    If the field is not an integer or double, or if the field does not yet exist, the transformation will set the field to the given value. If a maximum operation is applied where the field and the input value are of mixed types (that is - one is an integer and one is a double) the field takes on the type of the larger operand. If the operands are equivalent (e.g. 3 and 3.0), the field does not change. 0, 0.0, and -0.0 are all zero. The maximum of a zero stored value and zero input value is always the stored value. The maximum of any numeric value x and NaN is NaN.

                    func FieldTransformMinimum

                    func FieldTransformMinimum(n interface{}) transform

                      FieldTransformMinimum returns a special value that can be used with Set, Create, or Update that tells the server to set the field to the minimum of the field's current value and the given value.

                      The supported values are:

                      int, int8, int16, int32, int64
                      uint8, uint16, uint32
                      float32, float64
                      

                      If the field is not an integer or double, or if the field does not yet exist, the transformation will set the field to the given value. If a minimum operation is applied where the field and the input value are of mixed types (that is - one is an integer and one is a double) the field takes on the type of the smaller operand. If the operands are equivalent (e.g. 3 and 3.0), the field does not change. 0, 0.0, and -0.0 are all zero. The minimum of a zero stored value and zero input value is always the stored value. The minimum of any numeric value x and NaN is NaN.

                      func Increment

                      func Increment(n interface{}) transform

                        Increment is an alias for FieldTransformIncrement.

                        Example (Create)
                        Output:
                        
                        
                        Example (Update)
                        Output:
                        
                        

                        func MaxAttempts

                        func MaxAttempts(n int) maxAttempts

                          MaxAttempts is a TransactionOption that configures the maximum number of times to try a transaction. In defaults to DefaultTransactionMaxAttempts.

                          Types

                          type Client

                          type Client struct {
                          	// contains filtered or unexported fields
                          }

                            A Client provides access to the Firestore service.

                            func NewClient

                            func NewClient(ctx context.Context, projectID string, opts ...option.ClientOption) (*Client, error)

                              NewClient creates a new Firestore client that uses the given project.

                              Example
                              Output:
                              
                              

                              func (*Client) Batch

                              func (c *Client) Batch() *WriteBatch

                                Batch returns a WriteBatch.

                                Example
                                Output:
                                
                                

                                func (*Client) Close

                                func (c *Client) Close() error

                                  Close closes any resources held by the client.

                                  Close need not be called at program exit.

                                  func (*Client) Collection

                                  func (c *Client) Collection(path string) *CollectionRef

                                    Collection creates a reference to a collection with the given path. A path is a sequence of IDs separated by slashes.

                                    Collection returns nil if path contains an even number of IDs or any ID is empty.

                                    Example
                                    Output:
                                    
                                    

                                    func (*Client) CollectionGroup

                                    func (c *Client) CollectionGroup(collectionID string) *CollectionGroupRef

                                      CollectionGroup creates a reference to a group of collections that include the given ID, regardless of parent document.

                                      For example, consider: France/Cities/Paris = {population: 100} Canada/Cities/Montreal = {population: 90}

                                      CollectionGroup can be used to query across all "Cities" regardless of its parent "Countries". See ExampleCollectionGroup for a complete example.

                                      Example
                                      Output:
                                      
                                      

                                      func (*Client) Collections

                                      func (c *Client) Collections(ctx context.Context) *CollectionIterator

                                        Collections returns an iterator over the top-level collections.

                                        func (*Client) Doc

                                        func (c *Client) Doc(path string) *DocumentRef

                                          Doc creates a reference to a document with the given path. A path is a sequence of IDs separated by slashes.

                                          Doc returns nil if path contains an odd number of IDs or any ID is empty.

                                          Example
                                          Output:
                                          
                                          

                                          func (*Client) GetAll

                                          func (c *Client) GetAll(ctx context.Context, docRefs []*DocumentRef) (_ []*DocumentSnapshot, err error)

                                            GetAll retrieves multiple documents with a single call. The DocumentSnapshots are returned in the order of the given DocumentRefs. The return value will always contain the same number of DocumentSnapshots as the number of DocumentRefs in the input.

                                            If the same DocumentRef is specified multiple times in the input, the return value will contain the same number of DocumentSnapshots referencing the same document.

                                            If a document is not present, the corresponding DocumentSnapshot's Exists method will return false.

                                            Example
                                            Output:
                                            
                                            

                                            func (*Client) RunTransaction

                                            func (c *Client) RunTransaction(ctx context.Context, f func(context.Context, *Transaction) error, opts ...TransactionOption) (err error)

                                              RunTransaction runs f in a transaction. f should use the transaction it is given for all Firestore operations. For any operation requiring a context, f should use the context it is passed, not the first argument to RunTransaction.

                                              f must not call Commit or Rollback on the provided Transaction.

                                              If f returns nil, RunTransaction commits the transaction. If the commit fails due to a conflicting transaction, RunTransaction retries f. It gives up and returns an error after a number of attempts that can be configured with the MaxAttempts option. If the commit succeeds, RunTransaction returns a nil error.

                                              If f returns non-nil, then the transaction will be rolled back and this method will return the same error. The function f is not retried.

                                              Note that when f returns, the transaction is not committed. Calling code must not assume that any of f's changes have been committed until RunTransaction returns nil.

                                              Since f may be called more than once, f should usually be idempotent – that is, it should have the same result when called multiple times.

                                              Example
                                              Output:
                                              
                                              

                                              type CollectionGroupRef

                                              type CollectionGroupRef struct {
                                              
                                              	// Use the methods of Query on a CollectionGroupRef to create and run queries.
                                              	Query
                                              	// contains filtered or unexported fields
                                              }

                                                A CollectionGroupRef is a reference to a group of collections sharing the same ID.

                                                type CollectionIterator

                                                type CollectionIterator struct {
                                                	// contains filtered or unexported fields
                                                }

                                                  CollectionIterator is an iterator over sub-collections of a document.

                                                  func (*CollectionIterator) GetAll

                                                  func (it *CollectionIterator) GetAll() ([]*CollectionRef, error)

                                                    GetAll returns all the collections remaining from the iterator.

                                                    func (*CollectionIterator) Next

                                                    func (it *CollectionIterator) Next() (*CollectionRef, error)

                                                      Next returns the next result. Its second return value is iterator.Done if there are no more results. Once Next returns Done, all subsequent calls will return Done.

                                                      func (*CollectionIterator) PageInfo

                                                      func (it *CollectionIterator) PageInfo() *iterator.PageInfo

                                                        PageInfo supports pagination. See the google.golang.org/api/iterator package for details.

                                                        type CollectionRef

                                                        type CollectionRef struct {
                                                        
                                                        	// Parent is the document of which this collection is a part. It is
                                                        	// nil for top-level collections.
                                                        	Parent *DocumentRef
                                                        
                                                        	// The full resource path of the collection: "projects/P/databases/D/documents..."
                                                        	Path string
                                                        
                                                        	// ID is the collection identifier.
                                                        	ID string
                                                        
                                                        	// Use the methods of Query on a CollectionRef to create and run queries.
                                                        	Query
                                                        	// contains filtered or unexported fields
                                                        }

                                                          A CollectionRef is a reference to Firestore collection.

                                                          func (*CollectionRef) Add

                                                          func (c *CollectionRef) Add(ctx context.Context, data interface{}) (*DocumentRef, *WriteResult, error)

                                                            Add generates a DocumentRef with a unique ID. It then creates the document with the given data, which can be a map[string]interface{}, a struct or a pointer to a struct.

                                                            Add returns an error in the unlikely event that a document with the same ID already exists.

                                                            Example
                                                            Output:
                                                            
                                                            

                                                            func (*CollectionRef) Doc

                                                            func (c *CollectionRef) Doc(id string) *DocumentRef

                                                              Doc returns a DocumentRef that refers to the document in the collection with the given identifier.

                                                              Example
                                                              Output:
                                                              
                                                              

                                                              func (*CollectionRef) DocumentRefs

                                                              func (c *CollectionRef) DocumentRefs(ctx context.Context) *DocumentRefIterator

                                                                DocumentRefs returns references to all the documents in the collection, including missing documents. A missing document is a document that does not exist but has sub-documents.

                                                                func (*CollectionRef) NewDoc

                                                                func (c *CollectionRef) NewDoc() *DocumentRef

                                                                  NewDoc returns a DocumentRef with a uniquely generated ID.

                                                                  NewDoc will panic if crypto/rand cannot generate enough bytes to make a new doc ID.

                                                                  Example
                                                                  Output:
                                                                  
                                                                  

                                                                  type Direction

                                                                  type Direction int32

                                                                    Direction is the sort direction for result ordering.

                                                                    const (
                                                                    	// Asc sorts results from smallest to largest.
                                                                    	Asc Direction = Direction(pb.StructuredQuery_ASCENDING)
                                                                    
                                                                    	// Desc sorts results from largest to smallest.
                                                                    	Desc Direction = Direction(pb.StructuredQuery_DESCENDING)
                                                                    )

                                                                    type DocumentChange

                                                                    type DocumentChange struct {
                                                                    	Kind DocumentChangeKind
                                                                    	Doc  *DocumentSnapshot
                                                                    	// The zero-based index of the document in the sequence of query results prior to this change,
                                                                    	// or -1 if the document was not present.
                                                                    	OldIndex int
                                                                    	// The zero-based index of the document in the sequence of query results after this change,
                                                                    	// or -1 if the document is no longer present.
                                                                    	NewIndex int
                                                                    }

                                                                      A DocumentChange describes the change to a document from one query snapshot to the next.

                                                                      type DocumentChangeKind

                                                                      type DocumentChangeKind int

                                                                        DocumentChangeKind describes the kind of change to a document between query snapshots.

                                                                        const (
                                                                        	// DocumentAdded indicates that the document was added for the first time.
                                                                        	DocumentAdded DocumentChangeKind = iota
                                                                        	// DocumentRemoved indicates that the document was removed.
                                                                        	DocumentRemoved
                                                                        	// DocumentModified indicates that the document was modified.
                                                                        	DocumentModified
                                                                        )

                                                                        type DocumentIterator

                                                                        type DocumentIterator struct {
                                                                        	// contains filtered or unexported fields
                                                                        }

                                                                          DocumentIterator is an iterator over documents returned by a query.

                                                                          func (*DocumentIterator) GetAll

                                                                          func (it *DocumentIterator) GetAll() ([]*DocumentSnapshot, error)

                                                                            GetAll returns all the documents remaining from the iterator. It is not necessary to call Stop on the iterator after calling GetAll.

                                                                            Example
                                                                            Output:
                                                                            
                                                                            

                                                                            func (*DocumentIterator) Next

                                                                            func (it *DocumentIterator) Next() (*DocumentSnapshot, error)

                                                                              Next returns the next result. Its second return value is iterator.Done if there are no more results. Once Next returns Done, all subsequent calls will return Done.

                                                                              Example
                                                                              Output:
                                                                              
                                                                              

                                                                              func (*DocumentIterator) Stop

                                                                              func (it *DocumentIterator) Stop()

                                                                                Stop stops the iterator, freeing its resources. Always call Stop when you are done with a DocumentIterator. It is not safe to call Stop concurrently with Next.

                                                                                type DocumentRef

                                                                                type DocumentRef struct {
                                                                                	// The CollectionRef that this document is a part of. Never nil.
                                                                                	Parent *CollectionRef
                                                                                
                                                                                	// The full resource path of the document. A document "doc-1" in collection
                                                                                	// "coll-1" would be: "projects/P/databases/D/documents/coll-1/doc-1".
                                                                                	Path string
                                                                                
                                                                                	// The ID of the document: the last component of the resource path.
                                                                                	ID string
                                                                                	// contains filtered or unexported fields
                                                                                }

                                                                                  A DocumentRef is a reference to a Firestore document.

                                                                                  func (*DocumentRef) Collection

                                                                                  func (d *DocumentRef) Collection(id string) *CollectionRef

                                                                                    Collection returns a reference to sub-collection of this document.

                                                                                    Example
                                                                                    Output:
                                                                                    
                                                                                    

                                                                                    func (*DocumentRef) Collections

                                                                                    func (d *DocumentRef) Collections(ctx context.Context) *CollectionIterator

                                                                                      Collections returns an iterator over the immediate sub-collections of the document.

                                                                                      func (*DocumentRef) Create

                                                                                      func (d *DocumentRef) Create(ctx context.Context, data interface{}) (_ *WriteResult, err error)

                                                                                        Create creates the document with the given data. It returns an error if a document with the same ID already exists.

                                                                                        The data argument can be a map with string keys, a struct, or a pointer to a struct. The map keys or exported struct fields become the fields of the firestore document. The values of data are converted to Firestore values as follows:

                                                                                        - bool converts to Bool.
                                                                                        - string converts to String.
                                                                                        - int, int8, int16, int32 and int64 convert to Integer.
                                                                                        - uint8, uint16 and uint32 convert to Integer. uint, uint64 and uintptr are disallowed,
                                                                                          because they may be able to represent values that cannot be represented in an int64,
                                                                                          which is the underlying type of a Integer.
                                                                                        - float32 and float64 convert to Double.
                                                                                        - []byte converts to Bytes.
                                                                                        - time.Time and *ts.Timestamp convert to Timestamp. ts is the package
                                                                                          "github.com/golang/protobuf/ptypes/timestamp".
                                                                                        - *latlng.LatLng converts to GeoPoint. latlng is the package
                                                                                          "google.golang.org/genproto/googleapis/type/latlng". You should always use
                                                                                          a pointer to a LatLng.
                                                                                        - Slices convert to Array.
                                                                                        - *firestore.DocumentRef converts to Reference.
                                                                                        - Maps and structs convert to Map.
                                                                                        - nils of any type convert to Null.
                                                                                        

                                                                                        Pointers and interface{} are also permitted, and their elements processed recursively.

                                                                                        Struct fields can have tags like those used by the encoding/json package. Tags begin with "firestore:" and are followed by "-", meaning "ignore this field," or an alternative name for the field. Following the name, these comma-separated options may be provided:

                                                                                        - omitempty: Do not encode this field if it is empty. A value is empty
                                                                                          if it is a zero value, or an array, slice or map of length zero.
                                                                                        - serverTimestamp: The field must be of type time.Time. serverTimestamp
                                                                                          is a sentinel token that tells Firestore to substitute the server time
                                                                                          into that field. When writing, if the field has the zero value, the
                                                                                          server will populate the stored document with the time that the request
                                                                                          is processed. However, if the field value is non-zero it won't be saved.
                                                                                        
                                                                                        Example (Map)
                                                                                        Output:
                                                                                        
                                                                                        
                                                                                        Example (Struct)
                                                                                        Output:
                                                                                        
                                                                                        

                                                                                        func (*DocumentRef) Delete

                                                                                        func (d *DocumentRef) Delete(ctx context.Context, preconds ...Precondition) (_ *WriteResult, err error)

                                                                                          Delete deletes the document. If the document doesn't exist, it does nothing and returns no error.

                                                                                          Example
                                                                                          Output:
                                                                                          
                                                                                          

                                                                                          func (*DocumentRef) Get

                                                                                          func (d *DocumentRef) Get(ctx context.Context) (_ *DocumentSnapshot, err error)

                                                                                            Get retrieves the document. If the document does not exist, Get return a NotFound error, which can be checked with

                                                                                            status.Code(err) == codes.NotFound
                                                                                            

                                                                                            In that case, Get returns a non-nil DocumentSnapshot whose Exists method return false and whose ReadTime is the time of the failed read operation.

                                                                                            Example
                                                                                            Output:
                                                                                            
                                                                                            

                                                                                            func (*DocumentRef) Set

                                                                                            func (d *DocumentRef) Set(ctx context.Context, data interface{}, opts ...SetOption) (_ *WriteResult, err error)

                                                                                              Set creates or overwrites the document with the given data. See DocumentRef.Create for the acceptable values of data. Without options, Set overwrites the document completely. Specify one of the Merge options to preserve an existing document's fields. To delete some fields, use a Merge option with firestore.Delete as the field value.

                                                                                              Example
                                                                                              Output:
                                                                                              
                                                                                              
                                                                                              Example (Merge)
                                                                                              Output:
                                                                                              
                                                                                              

                                                                                              func (*DocumentRef) Snapshots

                                                                                                Snapshots returns an iterator over snapshots of the document. Each time the document changes or is added or deleted, a new snapshot will be generated.

                                                                                                Example
                                                                                                Output:
                                                                                                
                                                                                                

                                                                                                func (*DocumentRef) Update

                                                                                                func (d *DocumentRef) Update(ctx context.Context, updates []Update, preconds ...Precondition) (_ *WriteResult, err error)

                                                                                                  Update updates the document. The values at the given field paths are replaced, but other fields of the stored document are untouched.

                                                                                                  Example
                                                                                                  Output:
                                                                                                  
                                                                                                  

                                                                                                  type DocumentRefIterator

                                                                                                  type DocumentRefIterator struct {
                                                                                                  	// contains filtered or unexported fields
                                                                                                  }

                                                                                                    DocumentRefIterator is an iterator over DocumentRefs.

                                                                                                    func (*DocumentRefIterator) GetAll

                                                                                                    func (it *DocumentRefIterator) GetAll() ([]*DocumentRef, error)

                                                                                                      GetAll returns all the DocumentRefs remaining from the iterator.

                                                                                                      func (*DocumentRefIterator) Next

                                                                                                      func (it *DocumentRefIterator) Next() (*DocumentRef, error)

                                                                                                        Next returns the next result. Its second return value is iterator.Done if there are no more results. Once Next returns Done, all subsequent calls will return Done.

                                                                                                        func (*DocumentRefIterator) PageInfo

                                                                                                        func (it *DocumentRefIterator) PageInfo() *iterator.PageInfo

                                                                                                          PageInfo supports pagination. See the google.golang.org/api/iterator package for details.

                                                                                                          type DocumentSnapshot

                                                                                                          type DocumentSnapshot struct {
                                                                                                          	// The DocumentRef for this document.
                                                                                                          	Ref *DocumentRef
                                                                                                          
                                                                                                          	// Read-only. The time at which the document was created.
                                                                                                          	// Increases monotonically when a document is deleted then
                                                                                                          	// recreated. It can also be compared to values from other documents and
                                                                                                          	// the read time of a query.
                                                                                                          	CreateTime time.Time
                                                                                                          
                                                                                                          	// Read-only. The time at which the document was last changed. This value
                                                                                                          	// is initially set to CreateTime then increases monotonically with each
                                                                                                          	// change to the document. It can also be compared to values from other
                                                                                                          	// documents and the read time of a query.
                                                                                                          	UpdateTime time.Time
                                                                                                          
                                                                                                          	// Read-only. The time at which the document was read.
                                                                                                          	ReadTime time.Time
                                                                                                          	// contains filtered or unexported fields
                                                                                                          }

                                                                                                            A DocumentSnapshot contains document data and metadata.

                                                                                                            func (*DocumentSnapshot) Data

                                                                                                            func (d *DocumentSnapshot) Data() map[string]interface{}

                                                                                                              Data returns the DocumentSnapshot's fields as a map. It is equivalent to

                                                                                                              var m map[string]interface{}
                                                                                                              d.DataTo(&m)
                                                                                                              

                                                                                                              except that it returns nil if the document does not exist.

                                                                                                              Example
                                                                                                              Output:
                                                                                                              
                                                                                                              

                                                                                                              func (*DocumentSnapshot) DataAt

                                                                                                              func (d *DocumentSnapshot) DataAt(path string) (interface{}, error)

                                                                                                                DataAt returns the data value denoted by path.

                                                                                                                The path argument can be a single field or a dot-separated sequence of fields, and must not contain any of the runes "˜*/[]". Use DataAtPath instead for such a path.

                                                                                                                See DocumentSnapshot.DataTo for how Firestore values are converted to Go values.

                                                                                                                If the document does not exist, DataAt returns a NotFound error.

                                                                                                                Example
                                                                                                                Output:
                                                                                                                
                                                                                                                

                                                                                                                func (*DocumentSnapshot) DataAtPath

                                                                                                                func (d *DocumentSnapshot) DataAtPath(fp FieldPath) (interface{}, error)

                                                                                                                  DataAtPath returns the data value denoted by the FieldPath fp. If the document does not exist, DataAtPath returns a NotFound error.

                                                                                                                  Example
                                                                                                                  Output:
                                                                                                                  
                                                                                                                  

                                                                                                                  func (*DocumentSnapshot) DataTo

                                                                                                                  func (d *DocumentSnapshot) DataTo(p interface{}) error

                                                                                                                    DataTo uses the document's fields to populate p, which can be a pointer to a map[string]interface{} or a pointer to a struct.

                                                                                                                    Firestore field values are converted to Go values as follows:

                                                                                                                    - Null converts to nil.
                                                                                                                    - Bool converts to bool.
                                                                                                                    - String converts to string.
                                                                                                                    - Integer converts int64. When setting a struct field, any signed or unsigned
                                                                                                                      integer type is permitted except uint, uint64 or uintptr. Overflow is detected
                                                                                                                      and results in an error.
                                                                                                                    - Double converts to float64. When setting a struct field, float32 is permitted.
                                                                                                                      Overflow is detected and results in an error.
                                                                                                                    - Bytes is converted to []byte.
                                                                                                                    - Timestamp converts to time.Time.
                                                                                                                    - GeoPoint converts to *latlng.LatLng, where latlng is the package
                                                                                                                      "google.golang.org/genproto/googleapis/type/latlng".
                                                                                                                    - Arrays convert to []interface{}. When setting a struct field, the field
                                                                                                                      may be a slice or array of any type and is populated recursively.
                                                                                                                      Slices are resized to the incoming value's size, while arrays that are too
                                                                                                                      long have excess elements filled with zero values. If the array is too short,
                                                                                                                      excess incoming values will be dropped.
                                                                                                                    - Maps convert to map[string]interface{}. When setting a struct field,
                                                                                                                      maps of key type string and any value type are permitted, and are populated
                                                                                                                      recursively.
                                                                                                                    - References are converted to *firestore.DocumentRefs.
                                                                                                                    

                                                                                                                    Field names given by struct field tags are observed, as described in DocumentRef.Create.

                                                                                                                    Only the fields actually present in the document are used to populate p. Other fields of p are left unchanged.

                                                                                                                    If the document does not exist, DataTo returns a NotFound error.

                                                                                                                    Example
                                                                                                                    Output:
                                                                                                                    
                                                                                                                    

                                                                                                                    func (*DocumentSnapshot) Exists

                                                                                                                    func (d *DocumentSnapshot) Exists() bool

                                                                                                                      Exists reports whether the DocumentSnapshot represents an existing document. Even if Exists returns false, the Ref and ReadTime fields of the DocumentSnapshot are valid.

                                                                                                                      type DocumentSnapshotIterator

                                                                                                                      type DocumentSnapshotIterator struct {
                                                                                                                      	// contains filtered or unexported fields
                                                                                                                      }

                                                                                                                        DocumentSnapshotIterator is an iterator over snapshots of a document. Call Next on the iterator to get a snapshot of the document each time it changes. Call Stop on the iterator when done.

                                                                                                                        For an example, see DocumentRef.Snapshots.

                                                                                                                        func (*DocumentSnapshotIterator) Next

                                                                                                                          Next blocks until the document changes, then returns the DocumentSnapshot for the current state of the document. If the document has been deleted, Next returns a DocumentSnapshot whose Exists method returns false.

                                                                                                                          Next is not expected to return iterator.Done unless it is called after Stop. Rarely, networking issues may also cause iterator.Done to be returned.

                                                                                                                          func (*DocumentSnapshotIterator) Stop

                                                                                                                          func (it *DocumentSnapshotIterator) Stop()

                                                                                                                            Stop stops receiving snapshots. You should always call Stop when you are done with a DocumentSnapshotIterator, to free up resources. It is not safe to call Stop concurrently with Next.

                                                                                                                            type FieldPath

                                                                                                                            type FieldPath []string

                                                                                                                              A FieldPath is a non-empty sequence of non-empty fields that reference a value.

                                                                                                                              A FieldPath value should only be necessary if one of the field names contains one of the runes ".˜*/[]". Most methods accept a simpler form of field path as a string in which the individual fields are separated by dots. For example,

                                                                                                                              []string{"a", "b"}
                                                                                                                              

                                                                                                                              is equivalent to the string form

                                                                                                                              "a.b"
                                                                                                                              

                                                                                                                              but

                                                                                                                              []string{"*"}
                                                                                                                              

                                                                                                                              has no equivalent string form.

                                                                                                                              type Precondition

                                                                                                                              type Precondition interface {
                                                                                                                              	// contains filtered or unexported methods
                                                                                                                              }

                                                                                                                                A Precondition modifies a Firestore update or delete operation.

                                                                                                                                var Exists Precondition

                                                                                                                                  Exists is a Precondition that checks for the existence of a resource before writing to it. If the check fails, the write does not occur.

                                                                                                                                  func LastUpdateTime

                                                                                                                                  func LastUpdateTime(t time.Time) Precondition

                                                                                                                                    LastUpdateTime returns a Precondition that checks that a resource must exist and must have last been updated at the given time. If the check fails, the write does not occur.

                                                                                                                                    type Query

                                                                                                                                    type Query struct {
                                                                                                                                    	// contains filtered or unexported fields
                                                                                                                                    }

                                                                                                                                      Query represents a Firestore query.

                                                                                                                                      Query values are immutable. Each Query method creates a new Query; it does not modify the old.

                                                                                                                                      func (Query) Documents

                                                                                                                                      func (q Query) Documents(ctx context.Context) *DocumentIterator

                                                                                                                                        Documents returns an iterator over the query's resulting documents.

                                                                                                                                        Example
                                                                                                                                        Output:
                                                                                                                                        
                                                                                                                                        
                                                                                                                                        Example (Path_methods)

                                                                                                                                          This example is just like the one above, but illustrates how to use the XXXPath methods of Query for field paths that can't be expressed as a dot-separated string.

                                                                                                                                          Output:
                                                                                                                                          
                                                                                                                                          

                                                                                                                                          func (Query) EndAt

                                                                                                                                          func (q Query) EndAt(docSnapshotOrFieldValues ...interface{}) Query

                                                                                                                                            EndAt returns a new Query that specifies that results should end at the document with the given field values. See Query.StartAt for more information.

                                                                                                                                            Calling EndAt overrides a previous call to EndAt or EndBefore.

                                                                                                                                            func (Query) EndBefore

                                                                                                                                            func (q Query) EndBefore(docSnapshotOrFieldValues ...interface{}) Query

                                                                                                                                              EndBefore returns a new Query that specifies that results should end just before the document with the given field values. See Query.StartAt for more information.

                                                                                                                                              Calling EndBefore overrides a previous call to EndAt or EndBefore.

                                                                                                                                              func (Query) Limit

                                                                                                                                              func (q Query) Limit(n int) Query

                                                                                                                                                Limit returns a new Query that specifies the maximum number of first results to return. It must not be negative.

                                                                                                                                                func (Query) LimitToLast

                                                                                                                                                func (q Query) LimitToLast(n int) Query

                                                                                                                                                  LimitToLast returns a new Query that specifies the maximum number of last results to return. It must not be negative.

                                                                                                                                                  func (Query) Offset

                                                                                                                                                  func (q Query) Offset(n int) Query

                                                                                                                                                    Offset returns a new Query that specifies the number of initial results to skip. It must not be negative.

                                                                                                                                                    func (Query) OrderBy

                                                                                                                                                    func (q Query) OrderBy(path string, dir Direction) Query

                                                                                                                                                      OrderBy returns a new Query that specifies the order in which results are returned. A Query can have multiple OrderBy/OrderByPath specifications. OrderBy appends the specification to the list of existing ones.

                                                                                                                                                      The path argument can be a single field or a dot-separated sequence of fields, and must not contain any of the runes "˜*/[]".

                                                                                                                                                      To order by document name, use the special field path DocumentID.

                                                                                                                                                      func (Query) OrderByPath

                                                                                                                                                      func (q Query) OrderByPath(fp FieldPath, dir Direction) Query

                                                                                                                                                        OrderByPath returns a new Query that specifies the order in which results are returned. A Query can have multiple OrderBy/OrderByPath specifications. OrderByPath appends the specification to the list of existing ones.

                                                                                                                                                        func (Query) Select

                                                                                                                                                        func (q Query) Select(paths ...string) Query

                                                                                                                                                          Select returns a new Query that specifies the paths to return from the result documents. Each path argument can be a single field or a dot-separated sequence of fields, and must not contain any of the runes "˜*/[]".

                                                                                                                                                          An empty Select call will produce a query that returns only document IDs.

                                                                                                                                                          func (Query) SelectPaths

                                                                                                                                                          func (q Query) SelectPaths(fieldPaths ...FieldPath) Query

                                                                                                                                                            SelectPaths returns a new Query that specifies the field paths to return from the result documents.

                                                                                                                                                            An empty SelectPaths call will produce a query that returns only document IDs.

                                                                                                                                                            func (Query) Snapshots

                                                                                                                                                            func (q Query) Snapshots(ctx context.Context) *QuerySnapshotIterator

                                                                                                                                                              Snapshots returns an iterator over snapshots of the query. Each time the query results change, a new snapshot will be generated.

                                                                                                                                                              Example
                                                                                                                                                              Output:
                                                                                                                                                              
                                                                                                                                                              

                                                                                                                                                              func (Query) StartAfter

                                                                                                                                                              func (q Query) StartAfter(docSnapshotOrFieldValues ...interface{}) Query

                                                                                                                                                                StartAfter returns a new Query that specifies that results should start just after the document with the given field values. See Query.StartAt for more information.

                                                                                                                                                                Calling StartAfter overrides a previous call to StartAt or StartAfter.

                                                                                                                                                                func (Query) StartAt

                                                                                                                                                                func (q Query) StartAt(docSnapshotOrFieldValues ...interface{}) Query

                                                                                                                                                                  StartAt returns a new Query that specifies that results should start at the document with the given field values.

                                                                                                                                                                  StartAt may be called with a single DocumentSnapshot, representing an existing document within the query. The document must be a direct child of the location being queried (not a parent document, or document in a different collection, or a grandchild document, for example).

                                                                                                                                                                  Otherwise, StartAt should be called with one field value for each OrderBy clause, in the order that they appear. For example, in

                                                                                                                                                                  q.OrderBy("X", Asc).OrderBy("Y", Desc).StartAt(1, 2)
                                                                                                                                                                  

                                                                                                                                                                  results will begin at the first document where X = 1 and Y = 2.

                                                                                                                                                                  If an OrderBy call uses the special DocumentID field path, the corresponding value should be the document ID relative to the query's collection. For example, to start at the document "NewYork" in the "States" collection, write

                                                                                                                                                                  client.Collection("States").OrderBy(DocumentID, firestore.Asc).StartAt("NewYork")
                                                                                                                                                                  

                                                                                                                                                                  Calling StartAt overrides a previous call to StartAt or StartAfter.

                                                                                                                                                                  func (Query) Where

                                                                                                                                                                  func (q Query) Where(path, op string, value interface{}) Query

                                                                                                                                                                    Where returns a new Query that filters the set of results. A Query can have multiple filters. The path argument can be a single field or a dot-separated sequence of fields, and must not contain any of the runes "˜*/[]". The op argument must be one of "==", "!=", "<", "<=", ">", ">=", "array-contains", "array-contains-any", "in" or "not-in".

                                                                                                                                                                    func (Query) WherePath

                                                                                                                                                                    func (q Query) WherePath(fp FieldPath, op string, value interface{}) Query

                                                                                                                                                                      WherePath returns a new Query that filters the set of results. A Query can have multiple filters. The op argument must be one of "==", "!=", "<", "<=", ">", ">=", "array-contains", "array-contains-any", "in" or "not-in".

                                                                                                                                                                      type QuerySnapshot

                                                                                                                                                                      type QuerySnapshot struct {
                                                                                                                                                                      	// An iterator over the query results.
                                                                                                                                                                      	// It is not necessary to call Stop on this iterator.
                                                                                                                                                                      	Documents *DocumentIterator
                                                                                                                                                                      
                                                                                                                                                                      	// The number of results in this snapshot.
                                                                                                                                                                      	Size int
                                                                                                                                                                      
                                                                                                                                                                      	// The changes since the previous snapshot.
                                                                                                                                                                      	Changes []DocumentChange
                                                                                                                                                                      
                                                                                                                                                                      	// The time at which this snapshot was obtained from Firestore.
                                                                                                                                                                      	ReadTime time.Time
                                                                                                                                                                      }

                                                                                                                                                                        A QuerySnapshot is a snapshot of query results. It is returned by QuerySnapshotIterator.Next whenever the results of a query change.

                                                                                                                                                                        type QuerySnapshotIterator

                                                                                                                                                                        type QuerySnapshotIterator struct {
                                                                                                                                                                        	// The Query used to construct this iterator.
                                                                                                                                                                        	Query Query
                                                                                                                                                                        	// contains filtered or unexported fields
                                                                                                                                                                        }

                                                                                                                                                                          QuerySnapshotIterator is an iterator over snapshots of a query. Call Next on the iterator to get a snapshot of the query's results each time they change. Call Stop on the iterator when done.

                                                                                                                                                                          For an example, see Query.Snapshots.

                                                                                                                                                                          func (*QuerySnapshotIterator) Next

                                                                                                                                                                          func (it *QuerySnapshotIterator) Next() (*QuerySnapshot, error)

                                                                                                                                                                            Next blocks until the query's results change, then returns a QuerySnapshot for the current results.

                                                                                                                                                                            Next is not expected to return iterator.Done unless it is called after Stop. Rarely, networking issues may also cause iterator.Done to be returned.

                                                                                                                                                                            func (*QuerySnapshotIterator) Stop

                                                                                                                                                                            func (it *QuerySnapshotIterator) Stop()

                                                                                                                                                                              Stop stops receiving snapshots. You should always call Stop when you are done with a QuerySnapshotIterator, to free up resources. It is not safe to call Stop concurrently with Next.

                                                                                                                                                                              type Queryer

                                                                                                                                                                              type Queryer interface {
                                                                                                                                                                              	// contains filtered or unexported methods
                                                                                                                                                                              }

                                                                                                                                                                                A Queryer is a Query or a CollectionRef. CollectionRefs act as queries whose results are all the documents in the collection.

                                                                                                                                                                                type SetOption

                                                                                                                                                                                type SetOption interface {
                                                                                                                                                                                	// contains filtered or unexported methods
                                                                                                                                                                                }

                                                                                                                                                                                  A SetOption modifies a Firestore set operation.

                                                                                                                                                                                  var MergeAll SetOption = merge{/* contains filtered or unexported fields */}

                                                                                                                                                                                    MergeAll is a SetOption that causes all the field paths given in the data argument to Set to be overwritten. It is not supported for struct data.

                                                                                                                                                                                    func Merge

                                                                                                                                                                                    func Merge(fps ...FieldPath) SetOption

                                                                                                                                                                                      Merge returns a SetOption that causes only the given field paths to be overwritten. Other fields on the existing document will be untouched. It is an error if a provided field path does not refer to a value in the data passed to Set.

                                                                                                                                                                                      type Transaction

                                                                                                                                                                                      type Transaction struct {
                                                                                                                                                                                      	// contains filtered or unexported fields
                                                                                                                                                                                      }

                                                                                                                                                                                        Transaction represents a Firestore transaction.

                                                                                                                                                                                        func (*Transaction) Create

                                                                                                                                                                                        func (t *Transaction) Create(dr *DocumentRef, data interface{}) error

                                                                                                                                                                                          Create adds a Create operation to the Transaction. See DocumentRef.Create for details.

                                                                                                                                                                                          func (*Transaction) Delete

                                                                                                                                                                                          func (t *Transaction) Delete(dr *DocumentRef, opts ...Precondition) error

                                                                                                                                                                                            Delete adds a Delete operation to the Transaction. See DocumentRef.Delete for details.

                                                                                                                                                                                            func (*Transaction) DocumentRefs

                                                                                                                                                                                            func (t *Transaction) DocumentRefs(cr *CollectionRef) *DocumentRefIterator

                                                                                                                                                                                              DocumentRefs returns references to all the documents in the collection, including missing documents. A missing document is a document that does not exist but has sub-documents.

                                                                                                                                                                                              func (*Transaction) Documents

                                                                                                                                                                                              func (t *Transaction) Documents(q Queryer) *DocumentIterator

                                                                                                                                                                                                Documents returns a DocumentIterator based on given Query or CollectionRef. The results will be in the context of the transaction.

                                                                                                                                                                                                func (*Transaction) Get

                                                                                                                                                                                                  Get gets the document in the context of the transaction. The transaction holds a pessimistic lock on the returned document.

                                                                                                                                                                                                  func (*Transaction) GetAll

                                                                                                                                                                                                  func (t *Transaction) GetAll(drs []*DocumentRef) ([]*DocumentSnapshot, error)

                                                                                                                                                                                                    GetAll retrieves multiple documents with a single call. The DocumentSnapshots are returned in the order of the given DocumentRefs. If a document is not present, the corresponding DocumentSnapshot's Exists method will return false. The transaction holds a pessimistic lock on all of the returned documents.

                                                                                                                                                                                                    func (*Transaction) Set

                                                                                                                                                                                                    func (t *Transaction) Set(dr *DocumentRef, data interface{}, opts ...SetOption) error

                                                                                                                                                                                                      Set adds a Set operation to the Transaction. See DocumentRef.Set for details.

                                                                                                                                                                                                      func (*Transaction) Update

                                                                                                                                                                                                      func (t *Transaction) Update(dr *DocumentRef, data []Update, opts ...Precondition) error

                                                                                                                                                                                                        Update adds a new Update operation to the Transaction. See DocumentRef.Update for details.

                                                                                                                                                                                                        type TransactionOption

                                                                                                                                                                                                        type TransactionOption interface {
                                                                                                                                                                                                        	// contains filtered or unexported methods
                                                                                                                                                                                                        }

                                                                                                                                                                                                          A TransactionOption is an option passed to Client.Transaction.

                                                                                                                                                                                                          type Update

                                                                                                                                                                                                          type Update struct {
                                                                                                                                                                                                          	Path      string // Will be split on dots, and must not contain any of "˜*/[]".
                                                                                                                                                                                                          	FieldPath FieldPath
                                                                                                                                                                                                          	Value     interface{}
                                                                                                                                                                                                          }

                                                                                                                                                                                                            An Update describes an update to a value referred to by a path. An Update should have either a non-empty Path or a non-empty FieldPath, but not both.

                                                                                                                                                                                                            See DocumentRef.Create for acceptable values. To delete a field, specify firestore.Delete as the value.

                                                                                                                                                                                                            type WriteBatch

                                                                                                                                                                                                            type WriteBatch struct {
                                                                                                                                                                                                            	// contains filtered or unexported fields
                                                                                                                                                                                                            }

                                                                                                                                                                                                              A WriteBatch holds multiple database updates. Build a batch with the Create, Set, Update and Delete methods, then run it with the Commit method. Errors in Create, Set, Update or Delete are recorded instead of being returned immediately. The first such error is returned by Commit.

                                                                                                                                                                                                              func (*WriteBatch) Commit

                                                                                                                                                                                                              func (b *WriteBatch) Commit(ctx context.Context) (_ []*WriteResult, err error)

                                                                                                                                                                                                                Commit applies all the writes in the batch to the database atomically. Commit returns an error if there are no writes in the batch, if any errors occurred in constructing the writes, or if the Commmit operation fails.

                                                                                                                                                                                                                Example
                                                                                                                                                                                                                Output:
                                                                                                                                                                                                                
                                                                                                                                                                                                                

                                                                                                                                                                                                                func (*WriteBatch) Create

                                                                                                                                                                                                                func (b *WriteBatch) Create(dr *DocumentRef, data interface{}) *WriteBatch

                                                                                                                                                                                                                  Create adds a Create operation to the batch. See DocumentRef.Create for details.

                                                                                                                                                                                                                  func (*WriteBatch) Delete

                                                                                                                                                                                                                  func (b *WriteBatch) Delete(dr *DocumentRef, opts ...Precondition) *WriteBatch

                                                                                                                                                                                                                    Delete adds a Delete operation to the batch. See DocumentRef.Delete for details.

                                                                                                                                                                                                                    func (*WriteBatch) Set

                                                                                                                                                                                                                    func (b *WriteBatch) Set(dr *DocumentRef, data interface{}, opts ...SetOption) *WriteBatch

                                                                                                                                                                                                                      Set adds a Set operation to the batch. See DocumentRef.Set for details.

                                                                                                                                                                                                                      func (*WriteBatch) Update

                                                                                                                                                                                                                      func (b *WriteBatch) Update(dr *DocumentRef, data []Update, opts ...Precondition) *WriteBatch

                                                                                                                                                                                                                        Update adds an Update operation to the batch. See DocumentRef.Update for details.

                                                                                                                                                                                                                        type WriteResult

                                                                                                                                                                                                                        type WriteResult struct {
                                                                                                                                                                                                                        	// The time at which the document was updated, or created if it did not
                                                                                                                                                                                                                        	// previously exist. Writes that do not actually change the document do
                                                                                                                                                                                                                        	// not change the update time.
                                                                                                                                                                                                                        	UpdateTime time.Time
                                                                                                                                                                                                                        }

                                                                                                                                                                                                                          A WriteResult is returned by methods that write documents.

                                                                                                                                                                                                                          Directories

                                                                                                                                                                                                                          Path Synopsis
                                                                                                                                                                                                                          Package firestore is an auto-generated package for the Cloud Firestore API.
                                                                                                                                                                                                                          Package firestore is an auto-generated package for the Cloud Firestore API.
                                                                                                                                                                                                                          admin
                                                                                                                                                                                                                          Package apiv1 is an auto-generated package for the Google Cloud Firestore Admin API.
                                                                                                                                                                                                                          Package apiv1 is an auto-generated package for the Google Cloud Firestore Admin API.
                                                                                                                                                                                                                          Package firestore is an auto-generated package for the Cloud Firestore API.
                                                                                                                                                                                                                          Package firestore is an auto-generated package for the Cloud Firestore API.