Helper function to ensure correct context in JavaScript constructor. Alternative to `function Foo(...) { if (!(this instanceof Foo)) return new Foo(...); ... }`

Function.prototype.make.js

Function.prototype.make = function(self, args) {
  if (self instanceof args.callee) return self;
  var F = function() {};
  F.prototype = args.callee.prototype;
  var o = new F();
  F.prototype.constructor.apply(o, Array.prototype.slice.apply(args));
  return o;
};

function Foo(name) {
  var foo = Foo.make(this, arguments);
  foo.name = name;
  return foo;
}

var bar = new Foo('john');
var baz = Foo('paul');

console.log('bar is Foo => ' + (bar instanceof Foo));
console.log('baz is Foo => ' + (baz instanceof Foo));
console.log('bar.name => ' + bar.name);
console.log('baz.name => ' + baz.name);