code: func (j *Json) MustString(args ...string) string {
  	var def string
  
  	switch len(args) {
  	case 0:
  	case 1:
  		def = args[0]
  	default:
  		log.Panicf("MustString() received too many arguments %d", len(args))
  	}
  
  	s, err := j.String()
  	if err == nil {
  		return s
  	}
  
  	return def
  }
docs: // MustString guarantees the return of a `string` (with optional default)
  //
  // useful when you explicitly want a `string` in a single value return context:
  //     myFunc(js.Get("param1").MustString(), js.Get("optional_param").MustString("my_default"))