Question

I’m using Resig’s Simple JavaScript Inheritance to create my classes. The only thing I don’t like about it so far is that when I log an object created with this library to the console, it’s name is simply “Class”. My question is whether there is a way to modify his code so that I get the actual class name in the console instead. Here’s an example from Chrome’s console:

I would really like that name “Class” to be the actual name of the class I’ve created, in the way it would if you did the following:

I believe I know the reason why this happen’s with Resig’s library: the actual constructor function is simply named “Class”. Here’s the code for his library:

(function(){
  var initializing = false,
    // Determine if functions can be serialized
    fnTest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;

  // Create a new Class that inherits from this class
  Object.subClass = function(prop) {
    var _super = this.prototype;

    // Instantiate a base class (but only create the instance,
    // don't run the init constructor)
    initializing = true;
    var proto = new this();
    initializing = false;

    // Copy the properties over onto the new prototype
    for (var name in prop) {
      // Check if we're overwriting an existing function
      proto[name] = typeof prop[name] == "function" &&
        typeof _super[name] == "function" && fnTest.test(prop[name]) ?
        (function(name, fn){
          return function() {
            var tmp = this._super;

            // Add a new ._super() method that is the same method
            // but on the super-class
            this._super = _super[name];

            // The method only need to be bound temporarily, so we
            // remove it when we're done executing
            var ret = fn.apply(this, arguments);       
            this._super = tmp;

            return ret;
          };
        })(name, prop[name]) :
        prop[name];
    }

    // The dummy class constructor
    function Class() {
      // All construction is actually done in the init method
      if ( !initializing && this.init )
        this.init.apply(this, arguments);
    }

    // Populate our constructed prototype object
    Class.prototype = proto;

    // Enforce the constructor to be what we expect
    Class.constructor = Class;

    // And make this class extendable
    Class.subClass = arguments.callee;

    return Class;
  };
})();

You’ll find the Class() function about 2/3 of the way down. Does anyone know how to modify this code so that you get the actual name of the class in the console?

Answer 1

Toss in a change to Person.prototype.constructor when you’re creating Person:

var Person = (function() {
  var myConstructor = Class.extend({
    init: function(isDancing){
      this.dancing = isDancing;
    },
    dance: function(){
      return this.dancing;
    }
  });
  myConstructor.prototype.constructor = function Person(){};
  return myConstructor;
}());

I don’t think you could do it from within the Simple JavaScript Inheritance. You’d need the Person.prototype.constructor to be a named function, and I don’t think you can name a function without eval… and you have too much rep for me to explain why you shouldn’t do that 😉

---

No promises this doesn’t screw something up elsewhere though 😛