Implementation Testing

Test the implementation of new language features right in each browser.

The selection of functions is carried out from the implementation in at least one browser (in an instance of Firefox). Then we can see how these tests are, when other browsers implement them, and when you can use them in production.

This page applies only to the JavaScript language, but a similar page is devoted to testing the implementation of HTML 5 in browsers.

	Adding to JavaScript	Implemented?
Syntax	Scoping. Keyword let (1.7)
	Const (ES6)
	Destructive purpose: [a, b] = [x, y] (1.7)
	Asynk/avait
	ArrayBuffer and typed tables, Int32Array, etc. (ES6)
Massif	Reduced Array Method (1.8)
	Array Filtering Method (1.6)
	Array Map Method (1.6)
	Array's every and some methods (1.6)
	Array indexOf and lastIndexOf methods (1.6)
Object	Object.keys () (1.8.5)
	Object.entries () (ES2017)
Thong	String.trim () (1.8.1)
Objects	Selection set and has method, size (ES6) attribute
	Set of Map objects and methods, get, attribute size (ES6 )
	JSON Object (1.5)
	Proxy (ES6)
	Promised (TC39)
	Iterator (1.7)
	Generator. Keyword yield (1.7)
RED SMALL APPLE	Fetch

ES6 stands for ECMAScript version 6.

Read more about Array's new methods. Another page on the site concerns Harmony .

If you want to know what Microsoft intends to implement in Edge or not (and what is happening now), see "Platform Status."
Information about other browsers is not always updated .