context.js

// this example shows how you can enforce
// context with bind, even if you use .call
// or .apply

var FirstExample = function(name) {
  
  this.name = name;
  
  this.sayName = function() {
    return 'Hello ' + this.name + '!';
  }

  this.shoutName = function() {
    return 'Hey ' + this.name + '!!!!!!!';
  }.bind(this);
  
  return this;

};

var firstExample = new FirstExample('jon');

// here we can easily override context
firstExample.sayName(); // Hello jon!
firstExample.sayName.call({name: 'dave'}); // Hello dave!

// now lets try to do it while yelling!!!!!!!
firstExample.shoutName(); // Hey jon!!!!!!!
firstExample.shoutName.call({name: 'dave'}); // Hey jon!!!!!!!
firstExample.shoutName.apply({name: 'mr miage'}); // Hey jon!!!!!!!

// second example
// this shows that not only can we bind
// one constructor to an object, but we can
// affect the parents output :)

var SecondExample1 = function() {

  this.sayName = function() {
    return 'Hello ' + this.name;
  }

  this.setName = function(name) {
    this.name = name;
  }

  return this;

};

var SecondExample2 = function() {

  this.sayName = function() {
    return 'Hello ' + this.name + '!!!!';
  }

  this.setName = function(name) {
    this.name = name;
  }

  this.sayStuff = function() {
    return 'Stuff..';
  }

  return this;

};

var secondExample1 = new SecondExample1();
secondExample1.setName('jon');
secondExample1.sayName(); // Hello jon

var secondExample2 = SecondExample1.bind({})();
secondExample2.setName('dave');
secondExample2.sayName(); // Hello dave

var secondExample3 = SecondExample2.bind(secondExample1)();
secondExample3.setName('shake');
secondExample3.sayName(); // Hello shake!!!!

// whoa?
secondExample1.sayName(); // Hello shake!!!!
secondExample2.sayName(); // Hello dave
secondExample3.sayName(); // Hello shake!!!!

secondExample1.sayStuff(); // Stuff..