Global Back
Global Object refers to the top object, which is window
in browsers, while global
in Node.js.
In ES5, the property of a Global Object is same as a Global Variable.
window.a = 1;
console.log(a); /** => 1 */
a = 2;
console.log(window.a); /** => 2 */
In ES6, variables defined by var
and function
are still same as Global Variables. However, variables defined by let
, const
or class
do not belong to properties of the Global Object.
var a = 1;
/** in Node.js, it should be `global.a = 1;` or `this.a = 1;` */
console.log(window.a); /** => 1 */
let b = 1;
console.log(window.b); /** => undefined */