Javascript Enum To Corresponding String Value

Question

So I have this in the javascript for my page:

var TEST_ERROR  = {
        \'SUCCESS\'   :   0,
        \'FAIL\'      :   -1,
        \'ID_ERROR\'  :   -2
            


        

Answer 1

You could always have the values be objects of a particular type.

var TEST_ERROR = (function() {
  function ErrorValue(value, friendly) {
    this.value = value;
    this.friendly = friendly;
  }
  ErrorValue.prototype = {
    toString: function() { return this.friendly; },
    valueOf: function() { return this.value; }
  };
  return {
    'SUCCESS': new ErrorValue(0, 'Success'),
    'FAIL': new ErrorValue(1, 'Fail'),
    'ID_ERROR': new ErrorValue(2, 'ID error')
  };
})();

Now when you get a value of that type:

var err = testFunction(whatever);

you can get the string value with

alert(err.toString());

In fact you shouldn't even have to call .toString() explicitly, most of the time.