Make Accelerator a standalone JS type.

This makes menu and global-shortcut share the same code on accelerator.

docs/api/accelerator.md

@@ -0,0 +1,41 @@
+# Accelerator
+
+An accelerator is string that represents a keyboard shortcut, it can contain
+multiple modifiers and key codes, combined by the `+` character.
+
+Examples:
+
+* `Command+A`
+* `Ctrl+Shift+Z`
+
+## Platform notice
+
+On Linux and Windows, the `Command` key would not have any effect, you can
+use `CommandOrControl` which represents `Command` on OS X and `Control` on
+Linux and Windows to define some accelerators.
+
+## Available modifiers
+
+* `Command` (or `Cmd` for short)
+* `Control` (or `Ctrl` for short)
+* `CommandOrControl` (or `CmdOrCtrl` for short)
+* `Alt`
+* `Shift`
+
+## Available key codes
+
+* `0` to `9`
+* `A` to `Z`
+* `F1` to `F24`
+* Punctuations like `~`, `!`, `@`, `#`, `$`, etc.
+* `Space`
+* `Backspace`
+* `Delete`
+* `Insert`
+* `Return` (or `Enter` as alias)
+* `Up`, `Down`, `Left` and `Right`
+* `Home` and `End`
+* `PageUp` and `PageDown`
+* `Escape` (or `Esc` for short)
+* `VolumeUp`, `VolumeDown` and `VolumeMute`
+* `MediaNextTrack`, `MediaPreviousTrack`, `MediaStop` and `MediaPlayPause`

docs/api/global-shortcut.md

@@ -22,33 +22,23 @@ globalShortcut.unregister('ctrl+x');
 globalShortcut.unregisterAll();
 ```
 
-## globalShortcut.register(keycode, callback)
+## globalShortcut.register(accelerator, callback)
 
-* `keycode` String
+* `accelerator` [Accelerator](accelerator.md)
 * `callback` Function
 
-Registers a global shortcut of `keycode`, the `callback` would be called when
+Registers a global shortcut of `accelerator`, the `callback` would be called when
 the registered shortcut is pressed by user.
 
-`keycode` is a string to specify shortcut key, such as "ctrl+shift+a".
+## globalShortcut.isRegistered(accelerator)
 
-A `keycode` consists of modifier and key two parts:
+* `accelerator` [Accelerator](accelerator.md)
 
-__Modifiers__: control(ctrl), command(cmd), alt, shift, commandorcontrol(cmdorctrl).
+Returns whether shortcut of `accelerator` is registered.
 
-__Supported keys__: 0-9, a-z, up, down, left, right, home, end, pagedown, pageup,
-insert, delete, esc, space, backspace, tab, f1-f12, volumeup, volumedown, media 
-keys(medianextrack, mediaprevioustrack, mediastop, mediaplaypause).
+## globalShortcut.unregister(accelerator)
 
-## globalShortcut.isRegistered(keycode)
-
-* `keycode` String
-
-Return whether the shortcut is registered.
-
-## globalShortcut.unregister(keycode)
-
-* `keycode` String
+* `accelerator` [Accelerator](accelerator.md)
 
 Unregisters the global shortcut of `keycode`.
 

docs/api/menu-item.md

@@ -12,17 +12,9 @@
      `radio`
   * `label` String
   * `sublabel` String
-  * `accelerator` String - In the form of `Command+R`, `Ctrl+C`,
-    `Shift+Command+D`, `D`, etc.
+  * `accelerator` [Accelerator](accelerator.md)
   * `enabled` Boolean
   * `visible` Boolean
   * `checked` Boolean
   * `submenu` Menu - Should be specified for `submenu` type menu item, when
      it's specified the `type: 'submenu'` can be omitted for the menu item
-
-## Notes on accelerator
-
-On Linux and Windows, the `Command` key would not have any effect, you can
-use `CommandOrControl` which represents `Command` on OS X and `Control` on
-Linux and Windows to define some accelerators, you can also use its short
-alias `CmdOrCtrl`.