snappymail/dev/shortcuts.js

(win => {

const
	doc = document,
	meta = /Mac OS X/.test(navigator.userAgent) ? 'meta' : 'ctrl',
	_scopes = {},
	toArray = v => Array.isArray(v) ? v : v.split(/\s*,\s*/),

	keydown = event => {
		let key = (event.key || event.code || '').toLowerCase().replace(' ','space'),
			scopes = [];
		scope[key] && scopes.push(scope[key]);
		_scope !== 'all' && _scopes.all[key] && scopes.push(_scopes.all[key]);
		if (scopes.length && win.shortcuts.filter(event.target)) {
			let modifiers = [];
			event.altKey && modifiers.push('alt');
			event.ctrlKey && modifiers.push('ctrl');
			event.metaKey && modifiers.push('meta');
			event.shiftKey && modifiers.push('shift');
			modifiers = modifiers.join('+');
			scopes.forEach(actions => {
				if (actions[modifiers]) {
					// for each potential shortcut
					actions[modifiers].forEach(cmd => {
						try {
							// call the handler and stop the event if neccessary
							if (!event.defaultPrevented && cmd(event) === false) {
								event.preventDefault();
								event.stopPropagation();
							}
						} catch (e) {
							console.error(e);
						}
					});
				}
			});
		}
	};

let
	scope = {},
	_scope = 'all';

win.shortcuts = {
	on: () => doc.addEventListener('keydown', keydown),
	off: () => doc.removeEventListener('keydown', keydown),
	add: (keys, modifiers, scopes, method) => {
		if (method === undefined) {
			method = scopes;
			scopes = 'all';
		}
		toArray(scopes).forEach(scope => {
			if (!_scopes[scope]) {
				_scopes[scope] = {};
			}
			toArray(keys).forEach(key => {
				key = key.toLowerCase();
				if (!_scopes[scope][key]) {
					_scopes[scope][key] = {};
				}
				modifiers = toArray(modifiers)
					.map(key => 'meta' == key ? meta : key)
					.unique().sort().join('+');
				if (!_scopes[scope][key][modifiers]) {
					_scopes[scope][key][modifiers] = [];
				}
				_scopes[scope][key][modifiers].push(method);
			});
		});
	},
	setScope: value => {
		_scope = value || 'all';
		scope = _scopes[_scope] || {};
	},
	getScope: () => _scope,
	getMetaKey: () => meta,
	// ignore keydown in any element that supports keyboard input
	filter: node => !(!node.closest || node.closest('input,select,textarea,[contenteditable]'))
};

win.shortcuts.on();

})(this);