JavaScript bind

function.bind.js

// If you don't need new for bound functions do this
function bind(fn, c) {
  if (Function.prototype.bind &&
      fn.bind === Function.prototype.bind) {
    return Function.prototype.bind.apply(fn, 
      Array.prototype.slice.call(arguments, 1));
  }
  
  var args = Array.prototype.slice.call(arguments, 2);
  return function () {
    return fn.apply(c, args.concat(
      Array.prototype.slice.call(arguments)));
  }
}

// Else for new bound function support
function bind(fn, c) {
  var args = Array.prototype.slice.call(arguments, 2),
      ctor = function () {},
      bound = function () {
        return fn.apply(
          this instanceof ctor ? this : c,
          args.concat(
          Array.prototype.slice.call(arguments))       
        );
      };

  ctor.prototype = fn.prototype;
  bound.prototype = new ctor;

  return bound;
}

// or look at the following codes:
// * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind
// * https://github.com/jashkenas/underscore/blob/master/underscore.js