Golang json Marshalling operations - convert object to json string

encoding/json package provides json operations.

Marshalling

Marshalling means converting object to json.

Marshalling array

myArray := []string{"test 1", "test 2", "test 3"}
jsonStr, err := json.Marshal(myArray)
fmt.Println(string(jsonStr), err)

["test 1","test 2","test 3"] <nil>

Marshalling Map

myMap := make(map[string]interface{})
myMap["key 1"] = "val 1"
myMap["key 2"] = "val 2"
myMap["key int"] = 1234
myMap["key bool"] = true

jsonStr, err := json.Marshal(myMap)
fmt.Println(string(jsonStr), err)

{"key 1":"val 1","key 2":"val 2","key bool":true,"key int":1234} <nil>

Marshalling Object

type TestObj struct {
	FieldStr             string
	FieldInt             int
	FieldMightNullString *string
	SubTestObj           *TestObj
}

testStr := "Might null field"
myTestObj := TestObj{
	FieldStr:             "test str",
	FieldInt:             1,
	FieldMightNullString: &testStr,
	SubTestObj: &TestObj{
		FieldStr: "Test str sub",
		FieldInt: 2},
}

jsonStr, err := json.Marshal(myTestObj)
fmt.Println(string(jsonStr), err)

{"FieldStr":"test str","FieldInt":1,"FieldMightNullString":"Might null field","SubTestObj":{"FieldStr":"Test str sub","FieldInt":2,"FieldMightNullString":null,"SubTestObj":null}} <nil>

Marshalling as human readable text (json pretty print)

MarshalIndent function provides to generate pretty printed output

... 
jsonStr, err := json.MarshalIndent(myTestObj, "  ", "  ")
fmt.Println(string(jsonStr), err)

{
    "FieldStr": "test str",
    "FieldInt": 1,
    "FieldMightNullString": "Might null field",
    "SubTestObj": {
      "FieldStr": "Test str sub",
      "FieldInt": 2,
      "FieldMightNullString": null,
      "SubTestObj": null
    }
  } <nil>