SingleKeyDown jQuery plugin

singlekeydown.js

/**
 * SingleKeyDown
 *
 * Returns when a key has been pressed but does not trigger
 * if control or command is beeing pressed.
 *
 * Also, adds the name of the key in the event under the
 * `keyName` option. Includes special names for the keys
 * left & right.
 *
 * Example:
 *   $(document).singleKeyDown(function(e) {
 *     if (e.keyName == 'l')
 *       return alert('pressed L and not command L')
 *   })
 **/
$.fn.singleKeyDown = function(callback) {
  var upKeys = {}

  function keyName(code) {
    switch (code) {
      case 17:  return 'control'
      case 224: return 'command'
      case 37:  return 'left'
      case 39:  return 'right'
      default:  return String.fromCharCode(code)
    }
  }

  $(this).keydown(function(e) {
    e.keyName = keyName(e.keyCode)

    if (e.keyName == 'control' || e.keyName == 'command')
      upKeys[e.keyName] = true
    else if (!upKeys.control && !upKeys.command)
      return callback.call(this, e)

  }).keyup(function(e) {
    e.keyName = keyName(e.keyCode)

    if (e.keyName == 'control' || e.keyName == 'command')
      upKeys[e.keyName] = false
  })
}