Is there a better way to create an object-oriented class with jquery?

Question

I use the jquery extend function to extend a class prototype.

For example:

MyWidget = function(name_var) {
  this.init(name_var);
}

$.extend(MyWidget.prototype, {
   // object variables
   widget_name: '',

   init: function(widget_name) {
     // do initialization here
     this.widget_name = widget_name;
   },

   doSomething: function() {
     // an example object method
     alert('my name is '+this.widget_name);
   }
});


// example of using the class built above
var widget1 = new MyWidget('widget one');
widget1.doSomething();

Is there a better way to do this? Is there a cleaner way to create the class above with only one statement instead of two?

Answer 1

I quite like John Resig's Simple JavaScript Inheritance.

var MyWidget = Class.extend({
  init: function(widget_name){
    this.widget_name = widget_name;
  },

  doSomething: function() {
    alert('my name is ' + this.widget_name);
  }
});

NB: The "Class" object demonstrated above isn't included in jQuery itself - it's a 25 line snippet from Mr. jQuery himself, provided in the article above.

Answer 2

jQuery doesn't offer that. But Prototype does, via Class.create.

Answer 3

To summarize what I have learned so far:

Here is the Base function that makes Class.extend() work in jquery (Copied from Simple JavaScript Inheritance by John Resig):

// Inspired by base2 and Prototype
(function(){
  var initializing = false, fnTest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;

  // The base Class implementation (does nothing)
  this.Class = function(){};

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

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

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

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

    return Class;
  };
})();

Once you have run executed this code, then that makes the following code from insin's answer possible:

var MyWidget = Class.extend({
  init: function(widget_name){
    this.widget_name = widget_name;
  },

  doSomething: function() {
    alert('my name is ' + this.widget_name);
  }
});

This is a nice, clean solution. But I'm interested to see if anyone has a solution that doesn't require adding anything to jquery.

Answer 4

Devon, IMHO, your original solution seems less involved than the final solution. Sure, if JQuery were to incorporate that middle setup in a future release, that would make the final step somewhat simpler and cleaner, but for now, I would skip that middle step unless there's just some other major benefit - like working with LOTS of new Class definitions in JQuery.

Answer 5

Of course jQuery DOES OFFER that!! What do you think PLUGINS are for?

Please visit the HJS project plugin http://plugins.jquery.com/project/HJS. It may solve your problem.

Answer 6

this is long gone dead, but if anyone else searches for jquery creating class - check this plugin: http://plugins.jquery.com/project/HJS