code.delx.au - gnu-emacs-elpa/blob - README.md

   1 js2-mode
   2 ========
   3
   4 An improved JavaScript mode for GNU Emacs. Forked from <http://code.google.com/p/js2-mode/>.
   5
   6 Install
   7 =======
   8
   9     $ git clone git://github.com/mooz/js2-mode.git
  10     $ cd js2-mode
  11     $ emacs --batch -f batch-byte-compile js2-mode.el
  12
  13 _NOTE: Emacs may fail to byte compile js2-mode.el in interactive mode (e.g., `M-x byte-compile-file`). Following the above instruction is highly recommended. See https://github.com/mooz/js2-mode/issues/13 for details._
  14
  15 Then, place js2-mode.elc into your site-lisp directory.
  16
  17 In you emacs config:
  18
  19     (autoload 'js2-mode "js2-mode" nil t)
  20     (add-to-list 'auto-mode-alist '("\\.js$" . js2-mode))
  21
  22 See <http://code.google.com/p/js2-mode/wiki/InstallationInstructions> for details.
  23
  24 Differences between original js2-mode.el
  25 ========================================
  26
  27 Popular indentation style
  28 -------------------------
  29
  30 When `js2-consistent-level-indent-inner-bracket-p` is non-nil
  31
  32     [foo, bar, baz].forEach(function (v) {
  33         if (validate(v))
  34             process(v);
  35     });
  36
  37     [a, b, c].some(function (v) {
  38         return validate(v);
  39     });
  40
  41 When `js2-consistent-level-indent-inner-bracket-p` is nil
  42 (Same as original js2-mode's indentation)
  43
  44     [foo, bar, baz].forEach(function (v) {
  45                                 if (validate(v))
  46                                     process(v);
  47                             });
  48
  49     [a, b, c].some(function (v) {
  50                        return validate(v);
  51                    });
  52
  53 Pretty multi-line variable declaration
  54 --------------------------------------
  55
  56 In original js2-mode.el,
  57
  58     var foo = 10,
  59     bar = 20,
  60     baz = 30;
  61
  62 In this js2-mode.el, when the value `js2-pretty-multiline-decl-indentation-p` is non-nil,
  63
  64     var foo = 10,
  65         bar = 20,
  66         baz = 30;
  67
  68 Abbreviated destructuring assignments
  69 -------------------------------------
  70
  71     let {a, b}       = {a: 10, b: 20}; // Abbreviated   (Not supported in original js2-mode.el)
  72     let {a: a, b: b} = {a: 10, b: 20}; // Same as above (Supported in original js2-mode.el)
  73
  74     (function ({responseText}) { /* */ })(xhr); // As the argument of function
  75
  76     for (let [k, { name, age }] in Iterator(obj)) // nested
  77         print(k, name, age);
  78
  79 Expression closure in property value
  80 ------------------------------------
  81
  82     let worker = {
  83         get age() 20,
  84         get sex() "male",
  85         fire: function () _fire()
  86     };
  87
  88 Fix for odd indentation of "else if" with no braces
  89 ---------------------------------------------------
  90
  91 In original js2-mode.el,
  92
  93     if (foo)
  94         return foo;
  95     else if (bar)
  96     return bar;      // here
  97
  98 In this js2-mode.el,
  99
 100     if (foo)
 101         return foo;
 102     else if (bar)
 103         return bar;  // fixed
 104
 105 Fixes in Imenu support
 106 ----------------------
 107
 108 Supports element-get form:
 109
 110     foo["bar"] = function() {};
 111     foo[647] = function() {};
 112
 113 Proper position for functions in nested object literals:
 114
 115     foo = {
 116         bar: function() {}, // ok in original
 117         baz: {
 118              boop: function() {} // fixed here
 119         }
 120     }
 121
 122 Imenu support for function nesting
 123 ----------------------------------
 124
 125 Supports one level of nesting:
 126
 127     function foo() {
 128         function bar() { // shown as foo.bar
 129             function baz() {} // hidden
 130         }
 131     }
 132
 133 Top-level function can be anonymous wrapper:
 134
 135     (function() {
 136         var foo = function() {}; // shown as foo
 137     })();
 138
 139 Examples of output:
 140
 141 * [Underscore.js](https://github.com/documentcloud/underscore/blob/master/underscore.js)
 142 -> <https://gist.github.com/824262>
 143 * [Backbone.js](https://github.com/documentcloud/backbone/blob/master/backbone.js)
 144 -> <https://gist.github.com/824260>
 145
 146 No support for library-specific extension methods like _.extend.
 147
 148 Highlights undeclared/external variables
 149 ----------------------------------------
 150
 151 Original mode highlights them only on the left side of assignments:
 152
 153     var house;
 154     hose = new House(); // highlights "hose"
 155
 156 Here they are highlighted in all expressions:
 157
 158     function feed(fishes, food) {
 159         for each (var fish in fshes) { // highlights "fshes"
 160             food.feed(fsh); // highlights "fsh"
 161         }
 162         hood.discard(); // highlights "hood"
 163     }
 164
 165 Destructuring assignments and array comprehensions (JS 1.7) are supported:
 166
 167     let three, [one, two] = [1, 2];
 168     thee = one + two; // highlights "thee"
 169
 170     function revenue(goods) {
 171         // highlights "coast"
 172         return [price - coast for each ({price, cost} in goods)].reduce(add);
 173     }
 174
 175 Bugs
 176 ====
 177
 178 If you find problems, please report them to <http://github.com/mooz/js2-mode/issues>.