Shortcut JavaScript library

shortcut.js

/**
 * Shortcut Library
 * --
 * @version 2.01.B
 * @author Binny V A
 * @modifier Jan Kuča <jan@jankuca.com>
 * @license BSD
 */
(function (window) {
var document = window.document;

// work around for stupid Shift key bug created by using lowercase
// as a result the shift+num combination was broken
var shift_nums = {
	'`': '~',
	'1': '!',
	'2': '@',
	'3': '#',
	'4': '$',
	'5': '%',
	'6': '^',
	'7': '&',
	'8': '*',
	'9': '(',
	'0': ')',
	'-': '_',
	'=': '+',
	';': ':',
	'\'': '"',
	',': '<',
	'.': '>',
	'/': '?',
	'\\': '|'
};
// special key codes
var special_keys = {
	'esc': 27,
	'escape': 27,
	'tab': 9,
	'space': 32,
	'return': 13,
	'enter': 13,
	'backspace': 8,

	'scrolllock': 145,
	'scroll_lock': 145,
	'scroll': 145,
	'capslock': 20,
	'caps_lock': 20,
	'caps': 20,
	'numlock': 144,
	'num_lock': 144,
	'num': 144,
	
	'pause': 19,
	'break': 19,
	
	'insert': 45,
	'home': 36,
	'delete': 46,
	'end': 35,
	
	'pageup': 33,
	'page_up': 33,
	'pu': 33,

	'pagedown': 34,
	'page_down': 34,
	'pd': 34,

	'left': 37,
	'up': 38,
	'right': 39,
	'down': 40,

	'f1': 112,
	'f2': 113,
	'f3': 114,
	'f4': 115,
	'f5': 116,
	'f6': 117,
	'f7': 118,
	'f8': 119,
	'f9': 120,
	'f10': 121,
	'f11': 122,
	'f12': 123
};

var Shortcut = {
	'all_shortcuts': {}, // storage for all the shortcuts
	'add': function (shortcut_combination, callback, opt) {
		var default_options = {
			'type': 'keydown',
			'propagate': false,
			'disable_in_input': false,
			'target': document,
			'keycode': false
		};
		if (!opt) {
			opt = default_options;
		} else {
			var dfo;
			for (dfo in default_options) {
				if (default_options.hasOwnProperty(dfo) && opt[dfo] === undefined) {
					opt[dfo] = default_options[dfo];
				}
			}
		}

		var el = opt.target;
		if (typeof opt.target === 'string') {
			el = document.getElementById(opt.target);
		}
		shortcut_combination = shortcut_combination.toLowerCase();

		// keypress event listener
		var fn = function (event) {
			event = event || window.event;
			
			if (opt.disable_in_input) { // don't enable shortcut keys in input, and textarea fields
				var element;
				if (event.target) {
					element = event.target;
				} else if (event.srcElement) {
					element = event.srcElement;
				}
				if (element.nodeType === 3) {
					element = element.parentNode;
				}
				if (element.tagName === 'INPUT' || element.tagName === 'TEXTAREA') {
					return;
				}
			}
	
			// determine which key is pressed
			var code;
			if (event.keyCode) {
				code = event.keyCode;
			} else if (event.which) {
				code = event.which;
			}
			var character = String.fromCharCode(code).toLowerCase();
			
			if (code === 188) { // comma
				character = ',';
			}
			if (code === 190) { // period
				character = '.';
			}

			var keys = shortcut_combination.split('+');
			//Key Pressed - counts the number of valid keypresses - if it is same as the number of keys, the shortcut function is invoked
			var kp = 0;
	
			var modifiers = { 
				'shift': { 'wanted': false, 'pressed': false },
				'ctrl': { 'wanted': false, 'pressed': false },
				'alt': { 'wanted': false, 'pressed': false },
				'meta': { 'wanted': false, 'pressed': false } // meta is mac os-specific
			};
                        
			if (event.ctrlKey) {
				modifiers.ctrl.pressed = true;
			}
			if (event.shiftKey) {
				modifiers.shift.pressed = true;
			}
			if (event.altKey) {
				modifiers.alt.pressed = true;
			}
			if (event.metaKey) {
				modifiers.meta.pressed = true;
			}

			var i, k;
			for (i = 0; i < keys.length; ++i) {
				k = keys[i];
				++kp;
				// modifiers
				switch (k) {
				case 'ctrl':
				case 'control':
					modifiers.ctrl.wanted = true;
					break;
				case 'shift':
					modifiers.shift.wanted = true;
					break;
				case 'alt':
					modifiers.alt.wanted = true;
					break;
				case 'meta':
					modifiers.meta.wanted = true;
					break;
				default:
					if (k.length > 1) { // special key
						if (special_keys[k] === code) {
							break;
						} else if (opt.keycode && opt.keycode === code) {
							break;
						}
					} else { // regular key
						if (character === k) { // lowercase
							break;
						} else {
							if (shift_nums[character] && event.shiftKey) { // uppercase
								character = shift_nums[character];
							}
							if (character === k) {
								break;
							}
						}
					}
					--kp;
				}
			}
			
			if (kp === keys.length &&
				modifiers.ctrl.pressed === modifiers.ctrl.wanted &&
				modifiers.shift.pressed === modifiers.shift.wanted &&
				modifiers.alt.pressed === modifiers.alt.wanted &&
				modifiers.meta.pressed === modifiers.meta.wanted
			) {
				callback(event);
	
				if (!opt.propagate) { // stop the event
					if (event.stopPropagation) {
						event.stopPropagation();
						event.preventDefault();
					}
					return false;
				}
			}
		};
		
		if (this.all_shortcuts[shortcut_combination] === undefined) {
			this.all_shortcuts[shortcut_combination] = [];
		}
		this.all_shortcuts[shortcut_combination].push({
			'callback': fn, 
			'target': el, 
			'event': opt.type
		});
		// add the listener
		if (el.addEventListener) {
			el.addEventListener(opt.type, fn, false);
		} else if (el.attachEvent) {
			el.attachEvent('on' + opt.type, fn);
		} else {
			el['on' + opt.type] = fn;
		}
	},

	'remove': function (shortcut_combination, callback) {
		shortcut_combination = shortcut_combination.toLowerCase();
		var bindings = this.all_shortcuts[shortcut_combination];
		if (bindings === undefined) {
			return;
		}
		if (callback === undefined) {
			delete this.all_shortcuts[shortcut_combination];
		} else {
			var i, ii = bindings.length;
			var binding, el;
			for (i = 0; i < ii; ++i) {
				binding = bindings[i];
				el = binding.target;
				
				if (binding.callback === callback) {
					if (el.detachEvent) {
						el.detachEvent('on' + binding.event, callback);
					} else if (el.removeEventListener) {
						el.removeEventListener(binding.event, callback, false);
					} else {
						el['on' + binding.event] = false;
					}
				}
			}
		}
	}
};

window.Shortcut = Shortcut;
})(window);