Subversion Repositories qbpwcf-lib(archive)

/**
 * 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');
        }

        if (event._dispatched) {
                throw new Error('event already dispatched');
        }
        event._dispatched = true;

        // Force the event to be cancelable.
        event.cancelable = true;
        event.target = this;

        // Override stopImmediatePropagation() function.
        event.stopImmediatePropagation = function () {
                stopImmediatePropagation = true;
        };

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

        dummyListener = this['on' + type];
        if (typeof dummyListener === 'function') {
                listenersType.push(dummyListener);
        }

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

                listener.call(this, event);
        }

        return !event.defaultPrevented;
}