javascript-pour-les-jedis-episode-1-snippet-11.js

function Foo() {
  this.bar = function() {
    return this;
  }
}

// exemple 1
var foo = new Foo();
console.log(foo); //=> Foo
console.log(foo.bar() instanceof Foo); //=> true

// exemple 2
var foo1 = Foo();
console.log(typeof foo1); //=> undefined
console.log(typeof window.bar); //=> function