keymaster.js

Keymaster is a simple (100 LoC or so) micro-library for defining and dispatching keyboard shortcuts. It has no dependencies.

It’s a work in progress (e.g. beta), so spare me your nerdrage and instead contribute! Patches are welcome, but they are not guaranteed to make it in.

Usage

Include keymaster.min.js in your web app, by loading it as usual:

<script src="keymaster.min.js"></script>

Keymaster has no dependencies and can be used completely standalone. It should not interfere with any JavaScript libraries or frameworks.

Defining shortcuts

One global method is exposed, key which defines shortcuts when called directly.

// define short of 'a'
key('a', function(){ alert('you pressed a!') });

// returning false stops the event and prevents default browser events
key('ctrl+r', function(){ alert('stopped reload!'); return false });

// multiple shortcuts that do the same thing
key('⌘+r, ctrl+r', function(){ });

The handler method is called with two arguments set, the keydown event fired, and an object containing, among others, the following two properties:

shortcut: a string that contains the shortcut used, e.g. ctrl+r scope: a string describing the scope (or all)

key('⌘+r, ctrl+r', function(event, handler){
  console.log(handler.shortcut, handler.scope);
});

// "ctrl+r", "all"

Supported keys

Keymaster understands the following modifiers: ⇧, shift, option, ⌥, alt, ctrl, control, command, and ⌘.

The following special keys can be used for shortcuts: backspace, tab, clear, enter, return, esc, escape, space, up, down, left, right, home, end, pageup, pagedown, del, delete and f1 through f19.

Modifier key queries

At any point in time (even in code other than key shortcut handlers), you can query the key object for the state of modifier keys. This allows easy implementation of things like shift+click handlers. For example, key.shift is true if the shift key is currently pressed.

if(key.shift) alert('shift is pressed, OMGZ!');

Scopes

If you want to reuse the same shortcut for seperate areas in your single page app, Keymaster supports switching between scopes. Use the key.setScope method to set scope.

// define shortcuts with a scope
key('o, enter', 'issues', function(){ /* do something */ });
key('o, enter', 'files', function(){ /* do something else */ });

// set the scope (only 'all' and 'issues' shortcuts will be honored)
key.setScope('issues'); // default scope is 'all'

Notes

When an INPUT, SELECT or TEXTAREA element is focused, Keymaster doesn't process shortcuts.

Keymaster should work with any browser that fires keyup and keydown events, and is tested with IE (6+), Safari, Firefox and Chrome.

See http://madrobby.github.com/keymaster/ for a live demo.

CoffeeScript

If you're using CoffeeScript, configuring key shortcuts couldn't be simpler:

key 'a', -> alert('you pressed a!')

key '⌘+r, ctrl+r', ->
  alert 'stopped reload!'
  off

key 'o, enter', 'issues', ->
  whatevs()

alert 'shift is pressed, OMGZ!' if key.shift

Ender support

Add keymaster as a top level method to your Ender compilation.

$ ender add keymaster

Use it:

$.key('⌘+r', function () {
  alert('reload!')
})

Contributing

To contribute, please fork Keymaster, add your patch and tests for it (in the test/ folder) and submit a pull request.

TODOs

• Finish test suite
• Make behavior with INPUT / SELECT / TEXTAREA configurable

Keymaster is (c) 2011 Thomas Fuchs and may be freely distributed under the MIT license. See the MIT-LICENSE file.