jsondiff

README

jsondiff

jsnodiff provides functions to calculate JSON objects differences with gojq filter.

Synopsis

See examples on pkg.go.dev.

Installation

go get github.com/aereal/jsondiff

CLI

go install github.com/aereal/jsondiff/cmd/jsondiff@latest
jsondiff -only '.d' ./testdata/from.json ./testdata/to.json
# --- from.json
# +++ to.json
# @@ -1,2 +1,2 @@
# -4
# +3

See also

• gojq
  • Thanks to this library, it is able to filter JSON structures

License

See LICENSE file.

Documentation

Index

• Variables
• func Diff(from, to *Input, opts ...Option) (string, error)
• func DiffFromFiles(from, to fs.File, opts ...Option) (string, error)
• func DiffFromObjects(from, to interface{}, opts ...Option) (string, error)
• func ModifyValue(query *gojq.Query, x interface{}) (interface{}, error)
• func WithUpdate(query *gojq.Query) *gojq.Query
• type Input
  • func NewInputFromFile(f fs.File) (*Input, error)
• type Option
  • func Ignore(query *gojq.Query) Option
  • func Only(query *gojq.Query) Option

Examples

• DiffFromFiles
• DiffFromObjects (Ignore)
• DiffFromObjects (Only)

Variables

var ErrEitherOnlyOneOption = errors.New("either of only one of Ignore() or Only() must be specified")

Functions

func Diff

func Diff(from, to *Input, opts ...Option) (string, error)

Diff calculates differences with inputs.

func DiffFromFiles

func DiffFromFiles(from, to fs.File, opts ...Option) (string, error)

DiffFromFiles calculates differences with flies' contents.

Example

query, err := gojq.Parse(".d")
if err != nil {
	panic(err)
}
from, err := os.Open("./testdata/from.json")
if err != nil {
	panic(err)
}
to, err := os.Open("./testdata/to.json")
if err != nil {
	panic(err)
}
diff, err := DiffFromFiles(from, to, Only(query))
if err != nil {
	panic(err)
}
fmt.Print(diff)

Output:

--- from.json
+++ to.json
@@ -1,2 +1,2 @@
-4
+3

func DiffFromObjects

func DiffFromObjects(from, to interface{}, opts ...Option) (string, error)

DiffFromObjects calculates differences with from and to.

Example (Ignore)

query, err := gojq.Parse(".b, .c")
if err != nil {
	panic(err)
}
diff, err := DiffFromObjects(lhs, rhs, Ignore(query))
if err != nil {
	panic(err)
}
fmt.Println(diff)

Output:

--- from
+++ to
@@ -2,6 +2,6 @@
   "a": 1,
   "b": null,
   "c": null,
-  "d": 4
+  "d": 3
 }

Example (Only)

query, err := gojq.Parse(".d")
if err != nil {
	panic(err)
}
diff, err := DiffFromObjects(lhs, rhs, Only(query))
if err != nil {
	panic(err)
}
fmt.Println(diff)

Output:

--- from
+++ to
@@ -1,2 +1,2 @@
-4
+3

func ModifyValue

func ModifyValue(query *gojq.Query, x interface{}) (interface{}, error)

func WithUpdate

func WithUpdate(query *gojq.Query) *gojq.Query

Types

type Input

type Input struct {
	// Name is Input's name.
	//
	// It'll be used as patch's file name.
	Name string

	// X is an object decoded from JSON.
	X interface{}
}

Input represents a pair of the object that decoded from JSON and its name.

func NewInputFromFile

func NewInputFromFile(f fs.File) (*Input, error)

NewInputFromFile returns a new Input from file's name and contents.

type Option

type Option func(*opt)

Option is a function to modify Diff's behavior.

func Ignore

func Ignore(query *gojq.Query) Option

Ignore returns Option function that indicates the function to ignore structures pointed by the query.

func Only

func Only(query *gojq.Query) Option

Only returns Option function that indicates the function to calculate differences based on the structure pointed by the query.