How to declare the default value in go language structure and how to convert it into JSON data

go Language How the structure declares the default value How to translate into json data

// PanType  Definition type 
type PanType struct {
    
	Name     string      `json:"name"`
	Password string      `json:"password"`
	Children ChildrenPan `json:"children"`
}

// ErrorMsg  Definition type 
type ErrorMsg struct {
    
	//json Followed by an alias 
	Code int    `json:"code"`
	Msg  string `json:"msg"`
}

// Default initial value 
func newPanType(name string) PanType {
    
	str := PanType{
    
		Name:     name,
		Password: "wqtqw",
	}
	return str
}

// Initialization error code 
var msgErrorCode int = 4000

// Package error json
func newErrorMsg() bool {
    
	// Get error messages 
	msg := recover()
	// Force format to string 
	str2 := fmt.Sprintf("%s", msg)
	str := ErrorMsg{
    
		Code: msgErrorCode,
		Msg:  str2,
	}
	fmt.Println(msgErrorCode)
	jsonStr, _ := json.Marshal(str)
	jsonString := string(jsonStr)
	fmt.Println(jsonString)
	return true
}
func main() {
    
	// Code execution finished   Execution method 
	defer newErrorMsg()
	// The default method 
	str := newPanType("jump")
	// Modify the default password of the structure 
	str.Password = "easy_password"
	// Turn into Json character string 
	jsonStr, errMsg := json.Marshal(str)
	// Intentional error code 
	errMsg = errors.New("error")
	if errMsg != nil {
    
		// Modify the error code of the global variable 
		msgErrorCode = 4001
		// Rewrite the wrong name 
		errMsg = errors.New("update error")
		// Stop running   Throw out 
		panic(errMsg)
	}
	fmt.Println(string(jsonStr))
}