hokaccha · March 15, 2013 14:51
diff --git a/not_allow_without_new.js b/not_allow_without_new.js
 function Foo() {
  if (!(this instanceof Foo)) {
    throw new Error('called without new');
  }

  // initialize
 }

 var foo = Foo();
	function Foo() {
	if (!(this instanceof Foo)) {
	throw new Error('called without new');
	}

	// initialize
	}

	var foo = Foo();