node_modules/yaeti/lib/EventTarget.js

/**
 * Expose the _EventTarget class.
 */
module.exports = _EventTarget;

function _EventTarget() {
	// Do nothing if called for a native EventTarget object..
	if (typeof this.addEventListener === 'function') {
		return;
	}

	this._listeners = {};

	this.addEventListener = _addEventListener;
	this.removeEventListener = _removeEventListener;
	this.dispatchEvent = _dispatchEvent;
}

Object.defineProperties(_EventTarget.prototype, {
	listeners: {
		get: function () {
			return this._listeners;
		}
	}
});

function _addEventListener(type, newListener) {
	var
		listenersType,
		i, listener;

	if (!type || !newListener) {
		return;
	}

	listenersType = this._listeners[type];
	if (listenersType === undefined) {
		this._listeners[type] = listenersType = [];
	}

	for (i = 0; !!(listener = listenersType[i]); i++) {
		if (listener === newListener) {
			return;
		}
	}

	listenersType.push(newListener);
}

function _removeEventListener(type, oldListener) {
	var
		listenersType,
		i, listener;

	if (!type || !oldListener) {
		return;
	}

	listenersType = this._listeners[type];
	if (listenersType === undefined) {
		return;
	}

	for (i = 0; !!(listener = listenersType[i]); i++) {
		if (listener === oldListener) {
			listenersType.splice(i, 1);
			break;
		}
	}

	if (listenersType.length === 0) {
		delete this._listeners[type];
	}
}

function _dispatchEvent(event) {
	var
		type,
		listenersType,
		dummyListener,
		stopImmediatePropagation = false,
		i, listener;

	if (!event || typeof event.type !== 'string') {
		throw new Error('`event` must have a valid `type` property');
	}

	// Do some stuff to emulate DOM Event behavior (just if this is not a
	// DOM Event object)
	if (event._yaeti) {
		event.target = this;
		event.cancelable = true;
	}

	// Attempt to override the stopImmediatePropagation() method
	try {
		event.stopImmediatePropagation = function () {
			stopImmediatePropagation = true;
		};
	} catch (error) {}

	type = event.type;
	listenersType = (this._listeners[type] || []);

	dummyListener = this['on' + type];
	if (typeof dummyListener === 'function') {
		dummyListener.call(this, event);
	}

	for (i = 0; !!(listener = listenersType[i]); i++) {
		if (stopImmediatePropagation) {
			break;
		}

		listener.call(this, event);
	}

	return !event.defaultPrevented;
}