Golang Zero-Value JSON Serialization

empty_test.go

package main

import (
	"encoding/json"
	"github.com/stretchr/testify/assert"
	"testing"
)

type MyType struct {
	FieldA string `json:"field_a"`
	FieldB string `json:"field_b,omitempty"`

	// if we need to be able to omit a field OR use its zero-value, we'll need a pointer
	FieldC *string `json:"field_c,omitempty"`
	FieldD *string `json:"field_d,omitempty"`

	FieldE *string `json:"field_e"`
}

func Test_EmptyStuff(t *testing.T) {
	myString := ""
	mySurcharge := MyType{
		FieldB: "",
		FieldC: &myString,
	}

	bytes, err := json.MarshalIndent(mySurcharge, "", "  ")
	assert.Nil(t, err)

	println(string(bytes))

	expected := `{
  "field_a": "",
  "field_c": "",
  "field_e": null
}`
	assert.Equal(t, expected, string(bytes))

}