Question

I am reading this article – http://www.robertsosinski.com/2009/04/28/binding-scope-in-javascript/ – where a custom bind function is made.

Function.prototype.bind = function(scope) {
  var _function = this;

  return function() {
    return _function.apply(scope, arguments);
  }
}

alice = {
  name: "alice"
}

eve = {
  talk: function(greeting) {
    console.log(greeting + ", my name is " + this.name);
  }.bind(alice) // <- bound to "alice"
}

eve.talk("hello");
// hello, my name is alice

My question is this line in particlar

 return function() {
    return _function.apply(scope, arguments);
  }

Why is the return in _function.apply(scope, arguments); there? And what is it doing and what is being returned?
I removed that return and it still works.

Answer 1

Why is the return in _function.apply(scope, arguments); there? And what is it doing and what is being returned? I removed that return and it still works. 

This is there in case you want to return a value. Currently your talk function is not returning any value so you don’t need it. if you change your talk function to

eve = {
  talk: function(greeting) {
    return ( greeting + ", my name is " + this.name) ;
  }.bind(alice) // <- bound to "alice"
}

console.log(eve.talk("hello"));

Now you will realize why return is required