1 # History of user-visible changes
7 * [ES6 modules](http://www.2ality.com/2014/09/es6-modules-final.html).
8 * [Short-hand object literals](http://ariya.ofilabs.com/2013/02/es6-and-object-literal-property-value-shorthand.html).
9 * [Method definitions](http://ariya.ofilabs.com/2013/03/es6-and-method-definitions.html).
10 * ['u' and 'y' RegExp flags](https://mathiasbynens.be/notes/es6-unicode-regex).
11 * [Computed property names](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-object-initializer).
12 * [Class statements and expressions](https://github.com/lukehoban/es6features#classes).
13 * [Template strings](http://tc39wiki.calculist.org/es6/template-strings/), including tagged ones.
15 The variable `js2-allow-keywords-as-property-names` has been
16 removed. Instead we check if `js2-language-version` is 180 or highter.
22 * Unicode characters in identifiers (improved).
23 * [Delegating yield](http://wiki.ecmascript.org/doku.php?id=harmony:generators#delegating_yield).
24 * [ES6 numeric literals](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-literals-numeric-literals) (octal, binary).
25 * Harmony [array and generator comprehensions](http://wingolog.org/archives/2014/03/07/es6-generator-and-array-comprehensions-in-spidermonkey).
31 * [Arrow functions](http://wiki.ecmascript.org/doku.php?id=harmony:arrow_function_syntax)
32 * [Generators](http://wiki.ecmascript.org/doku.php?id=harmony:generators)
33 * [Spread operator](http://wiki.ecmascript.org/doku.php?id=harmony:spread)
37 ### Support for JSLint global declaration
39 See the docstring for `js2-include-jslint-globals`.
43 ### We don't rebind `RET` anymore
45 Because well-behaving major modes aren't supposed to do that.
47 So pressing it won't continue a block comment, or turn a string into a concatenation.
48 Pressing `M-j`, however, will.
50 The options `js2-indent-on-enter-key` and `js2-enter-indents-newline` were also removed.
52 To bring back the previous behavior, put this in your init file:
55 (eval-after-load 'js2-mode
56 '(define-key js2-mode-map (kbd "RET") 'js2-line-break))
61 ### Support for [default](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/default_parameters) and [rest](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/rest_parameters) parameters
65 ### Support for [for..of loops](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of)
69 ### Popular indentation style
72 [foo, bar, baz].forEach(function (v) {
77 [a, b, c].some(function (v) {
82 ### Pretty multiline variable declaration
92 In this mode when the value of `js2-pretty-multiline-declarations` is non-nil,
100 ### Abbreviated destructuring assignments
103 let {a, b} = {a: 10, b: 20}; // Abbreviated (Not supported in the original mode)
104 let {a: a, b: b} = {a: 10, b: 20}; // Same as above (Supported in the original mode)
106 (function ({responseText}) { /* */ })(xhr); // As the argument of function
108 for (let [k, { name, age }] in Iterator(obj)) // nested
112 ### Expression closure in property value
118 fire: function () _fire()
122 ### Fix for odd indentation of "else if" with no braces
124 In the original mode,
142 ### Imenu support for function nesting
144 Supports function nesting and anonymous wrappers:
148 var foo = function() {
149 function bar() { // shown as foo.bar.<definition-1>
150 function baz() {} // foo.bar.baz
151 var qux = function() {}; // foo.bar.quux
159 * [jQuery 1.5](https://gist.github.com/845449)
160 * [Underscore.js](https://gist.github.com/824262)
161 * [Backbone.js](https://gist.github.com/824260)
163 For library-specific extension methods like `$.extend` and `dojo.declare`, see [js2-imenu-extras](/mooz/js2-mode/blob/master/js2-imenu-extras.el).
165 ### Undeclared/external variables highlighting
167 Original mode highlights them only on the left side of assignments:
171 hose = new House(); // highlights "hose"
174 Here they are highlighted in all expressions:
177 function feed(fishes, food) {
178 for each (var fish in fshes) { // highlights "fshes"
179 food.feed(fsh); // highlights "fsh"
181 hood.discard(); // highlights "hood"
185 Destructuring assignments and array comprehensions (JS 1.7) are supported:
188 let three, [one, two] = [1, 2];
189 thee = one + two; // highlights "thee"
191 function revenue(goods) {
192 // highlights "coast"
193 return [price - coast for each ({price, cost} in goods)].reduce(add);