README
¶
and you shall receive.
:warning: From version `v0.3.0`, the package requires [Go 1.17+](https://golang.org/doc/install), due to the usage of new additions to the reflect package.
Use
package main
import "json"
import "github.com/simonnilsson/ask"
func main() {
// Use parsed JSON as source data
var object map[string]interface{}
json.Unmarshal([]byte(`{
"a": [{
"b": {
"c": 3
}
}]
}`), &object)
// Extract the 3
res, ok := ask.For(object, "a[0].b.c").Int(0)
fmt.Println(res, ok)
// Output: 3 true
// Attempt extracting a string at path .d that does not exist
res2, ok := ask.ForArgs(object, "a", 0, "b", "d").String("nothing")
fmt.Println(res2, ok)
// Output: nothing false
}
API
Internally ask uses type assertions to traverse down the path supplied. Each invocation starts by calling For() with your data structure source and the path in this structure to extract. You can also use ForArgs() if want to supply each part of the path as a seperate argument, this can be usefull if your field names contain dots for example. The same accessors used in For can be used in ForArgs, but ForArgs can also take integers for slice indexes.
For(source interface{}, path string) *Answer
ForArgs(source interface{}, parts ...interface{}) *Answer
Additional paths can be traversed by calling Path()/PathArgs() on the resulting answer.
(a *Answer) Path(path string) *Answer
(a *Answer) PathArgs(parts ...interface{}) *Answer
Type assertion
After receiving an *Answer from a call to For() it can be asserted to a type. The methods for this is seen below. Each function takes a default value as a parameter that will be returned in case the value can not be asserted from the answer. A second return value is used to indicate if the assertion was successful.
(a *Answer) String(d string) (string, bool)
(a *Answer) Bool(d bool) (bool, bool)
(a *Answer) Int(d int64) (int64, bool)
(a *Answer) Uint(d uint64) (uint64, bool)
(a *Answer) Float(d float64) (float64, bool)
(a *Answer) Slice(d []interface{}) ([]interface{}, bool)
(a *Answer) Map(d map[string]interface{}) (map[string]interface{}, bool)
If a number is found but it is of different type than requested it will be casted to desired type and return success. If the value would not fit within the valid range of requested type the operation will fail however and the default parameter will be returned instead.
Two additional methods are available, one to check if the answer has a value (not nil) and one to return the raw value as a interface{}.
(a *Answer) Exists() bool
(a *Answer) Value() interface{}
For full documentation see pkg.go.dev.
License
Documentation
¶
Overview ¶
Package ask provides a simple way of accessing nested properties in maps and arrays. Works great in combination with encoding/json and other packages that "Unmarshal" arbitrary data into Go data-types. Inspired by the get function in the lodash javascript library.
Example ¶
// Use parsed JSON as source data
var object map[string]interface{}
json.Unmarshal([]byte(`{
"a": [{
"b": {
"c": 3
}
}]
}`), &object)
// Extract the 3
res, ok := For(object, "a[0].b.c").Int(0)
fmt.Println(res, ok)
// Attempt extracting a string at path .d that does not exist
res2, ok := For(object, "a[0].b.d").String("nothing")
fmt.Println(res2, ok)
Output: 3 true nothing false
Index ¶
- type Answer
- func (a *Answer) Bool(d bool) (bool, bool)
- func (a *Answer) Exists() bool
- func (a *Answer) Float(d float64) (float64, bool)
- func (a *Answer) Int(d int64) (int64, bool)
- func (a *Answer) Map(d map[string]interface{}) (map[string]interface{}, bool)
- func (a *Answer) Path(path string) *Answer
- func (a *Answer) PathArgs(parts ...interface{}) *Answer
- func (a *Answer) Slice(d []interface{}) ([]interface{}, bool)
- func (a *Answer) String(d string) (string, bool)
- func (a *Answer) Uint(d uint64) (uint64, bool)
- func (a *Answer) Value() interface{}
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Answer ¶
type Answer struct {
// contains filtered or unexported fields
}
Answer holds result of call to For, use one of its methods to extract a value.
func ForArgs ¶ added in v0.4.0
func ForArgs(source interface{}, parts ...interface{}) *Answer
ForArgs is used to select a path using individual arguments from source to return as answer.
func (*Answer) Bool ¶
Bool attempts asserting answer as a bool. The first return value is the result, and the second indicates if the operation was successful. If not successful the first return value will be set to the d parameter.
func (*Answer) Float ¶
Float attempts asserting answer as a float64. Casting from other number types will be done if necessary. The first return value is the result, and the second indicates if the operation was successful. If not successful the first return value will be set to the d parameter.
func (*Answer) Int ¶
Int attempts asserting answer as a int64. Casting from other number types will be done if necessary. The first return value is the result, and the second indicates if the operation was successful. If not successful the first return value will be set to the d parameter.
func (*Answer) Map ¶
Map attempts asserting answer as a map[string]interface{}. The first return value is the result, and the second indicates if the operation was successful. If not successful the first return value will be set to the d parameter.
func (*Answer) PathArgs ¶ added in v0.4.0
PathArgs does the same thing as ForArgs but uses existing answer as source.
func (*Answer) Slice ¶
Slice attempts asserting answer as a []interface{}. The first return value is the result, and the second indicates if the operation was successful. If not successful the first return value will be set to the d parameter.
func (*Answer) String ¶
String attempts asserting answer as a string. The first return value is the result, and the second indicates if the operation was successful. If not successful the first return value will be set to the d parameter.
Source Files