golib-json

A modified go "encoding/json" package that may writes struct field names in snake_case, lowerCamelCase, and lowercase.

Snake-cased marshaling and unmarshalling.

This package is almost-compatible with Go standard encoding/json package, except for a few additional functions. Most important functions added are MarshalSnakeCase() and UnmarshalSnakeCase(). As the name implies, MarshalSnakeCase() converts Go's CamelCase named members to snake_case named JSON field members. UnmarshalSnakeCase() is vice versa.

lowerCamelCase / lowercased marshalling/unmarshalling

function MarshalLowerCamelCase() and UnmarshalLowerCamelCase() handles JSON field names in lowerCamelCase, that means each word is capitalized except for the first word. Also, function MarshalLowerCase() and UnmarshalLowerCase() handles JSON field names in lowercase, that means all words are lowercased and concatenated without spaces.

Example

package main

import (
	"fmt"

	json "github.com/mixcode/golib-json-snake"
)

func main() {
	type st struct {
		Name          string // JSON object name will be "name"
		AnotherName   string // JSON object name will be "another_name"
		ExplicitCamel string `json:"ExplicitCamel"` // If a name tag is explicitly set, the name will be used as-is
		ExplicitSnake string `json:"explicit_snake"`
		Empty         int
	}

	in := st{"name", "another_name", "camel", "snake", 0}

	// encode with snake case
	encoded, err := json.MarshalSnakeCase(&in, false)
	if err != nil {
		panic(err)
	}
	fmt.Println(string(encoded))

	// Output:
	// {"name":"name","another_name":"another_name","ExplicitCamel":"camel","explicit_snake":"snake","empty":0}
}

Decoding of pre-set structs in "map[string]any" variables

Standard Go encoding/json package can unmarshal any JSON string into map[string]any type. In this case, child objects are also unmarshalled to map[string]any type.

In this package, child objects could be unmarshalled into proper structs if they are pre-placed to the map.

Example

package main

import (
	"fmt"

	json "github.com/mixcode/golib-json-snake"
)

func main() {
	// a custom struct
	type myStruct struct {
		Name string
		Yes  bool
	}

	m := make(map[string]any) // A universal map to decode a JSON
	m["payload"] = myStruct{} // If we know a exact type of an object, we can pre-set a receiver for the object

	// the 'payload' member in supplied json will be decoded to myStruct placed at m["payload"]
	err := json.UnmarshalSnakeCase([]byte(`{"ok":true,"payload":{"name":"mixcode","yes":true}}`), &m)
	if err != nil {
		panic(err)
	}

	// print the result
	var p myStruct = m["payload"].(myStruct)
	fmt.Printf("%v", p)
	// Output:
	//{mixcode true}
}