blockscope.js

// results from console.log() tested in Chrome 58, Firefox 51, Safari 10.0
// block scope
{
	function foo() { return 1; }
}
// returns "1"
console.log( foo() );

// IIFE
(function() {
	function foo() { return 2; }
})();
// returns "1"
console.log( foo() );

// now let's go to strict mode, inside an IIFE to isolate the test
(function() {
	"use strict";
	{
		function bar() { return 3; }
	}
	console.log( bar() ); // throws an error!
})();