javascript mixins

1.js

var foo = {
  doSomething: function(){
    // ...
  }
}

var bar = {};
bar.doSomething = foo.doSomething;

2.js

var foo = {
  baz: function(){ 
    // ...
  },

  config: [ ... ]
}

var bar = {
  config: { ... }
};

// ECMAScript "bind"
bar.baz = foo.baz.bind(foo);

// Undescore "bind"
bar.baz = _.bind(foo.baz, foo);

// ... many more options

3.js

Marionette.addEventBinder = function(target){

  // create the "source" of the functionality i need
  var eventBinder = new Marionette.EventBinder();

  // add the methods i need to the target object, binding them correctly
  target.bindTo = _.bind(eventBinder.bindTo, eventBinder);
  target.unbindFrom = _.bind(eventBinder.unbindFrom, eventBinder);
  target.unbindAll = _.bind(eventBinder.unbindAll, eventBinder);
};



// use the mixin method
var myApp = new Marionette.Application();
Marionette.addEventBinder(myApp);

4.js

// build a mixin function to take a target that receives the mixin, 
// a source that is the mixin, and a list of methods / attributes to
// copy over to the target

function mixInto(target, source, methodNames){

  // ignore the actual args list and build from arguments so we can
  // be sure to get all of the method names
  var args = Array.prototype.slice.apply(arguments);
  target = args.shift();
  source = args.shift();
  methodNames = args;

  var method;
  var length = methodNames.length;
  for(var i = 0; i < length; i++){
    method = methodNames[i];

    // bind the function from the source and assign the
    // bound function to the target
    target[method] = _.bind(source[method], source);
  }

}


// make use of the mixin function
var myApp = new Marionette.Application();
mixInto(myApp, Marionette.EventBinder, "bindTo", "unbindFrom", "unbindAll");

5.js

// build a mixin function to take a target that receives the mixin, 
// a source that is the mixin, and a list of methods / attributes to
// copy over to the target

function mixInto(target, source, methodNames){

  // ignore the actual args list and build from arguments so we can
  // be sure to get all of the method names
  var args = Array.prototype.slice.apply(arguments);
  target = args.shift();
  source = args.shift();
  methodNames = args;

  var method;
  var length = methodNames.length;
  for(var i = 0; i < length; i++){
    method = methodNames[i];

    // build a function with a closure around the source
    // and forward the method call to the source, passing
    // along the method parameters and setting the context
    target[method] = function(){
      var args = Array.prototype.slice(arguments);
      source[method].apply(source, args);
    }

  }

}


// make use of the mixin function
var myApp = new Marionette.Application();
mixInto(myApp, Marionette.EventBinder, "bindTo", "unbindFrom", "unbindAll");