# Yahoo! UI Library

### event-custom 3.3.0

Yahoo! UI Library > event-custom > event-facade.js (source view)
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    /**
     * Adds event facades, preventable default behavior, and bubbling.
     * events.
     * @module event-custom
     * @submodule event-custom-complex
     */

    var FACADE,
        FACADE_KEYS,
        EMPTY = {},
        CEProto = Y.CustomEvent.prototype,
        ETProto = Y.EventTarget.prototype;

    /**
     * Wraps and protects a custom event for use when emitFacade is set to true.
     * Requires the event-custom-complex module
     * @class EventFacade
     * @param e {Event} the custom event
     * @param currentTarget {HTMLElement} the element the listener was attached to
     */

    Y.EventFacade = function(e, currentTarget) {

        e = e || EMPTY;

        this._event = e;

        /**
         * The arguments passed to fire
         * @property details
         * @type Array
         */
        this.details = e.details;

        /**
         * The event type, this can be overridden by the fire() payload
         * @property type
         * @type string
         */
        this.type = e.type;

        /**
         * The real event type
         * @property type
         * @type string
         */
        this._type = e.type;

        //////////////////////////////////////////////////////

        /**
         * Node reference for the targeted eventtarget
         * @propery target
         * @type Node
         */
        this.target = e.target;

        /**
         * Node reference for the element that the listener was attached to.
         * @propery currentTarget
         * @type Node
         */
        this.currentTarget = currentTarget;

        /**
         * Node reference to the relatedTarget
         * @propery relatedTarget
         * @type Node
         */
        this.relatedTarget = e.relatedTarget;

    };

    Y.extend(Y.EventFacade, Object, {

        /**
         * Stops the propagation to the next bubble target
         * @method stopPropagation
         */
        stopPropagation: function() {
            this._event.stopPropagation();
            this.stopped = 1;
        },

        /**
         * Stops the propagation to the next bubble target and
         * prevents any additional listeners from being exectued
         * on the current target.
         * @method stopImmediatePropagation
         */
        stopImmediatePropagation: function() {
            this._event.stopImmediatePropagation();
            this.stopped = 2;
        },

        /**
         * Prevents the event's default behavior
         * @method preventDefault
         */
        preventDefault: function() {
            this._event.preventDefault();
            this.prevented = 1;
        },

        /**
         * Stops the event propagation and prevents the default
         * event behavior.
         * @method halt
         * @param immediate {boolean} if true additional listeners
         * on the current target will not be executed
         */
        halt: function(immediate) {
            this._event.halt(immediate);
            this.prevented = 1;
            this.stopped = (immediate) ? 2 : 1;
        }

    });

    CEProto.fireComplex = function(args) {

        var es, ef, q, queue, ce, ret, events, subs, postponed,
            self = this, host = self.host || self, next, oldbubble;

        if (self.stack) {
            // queue this event if the current item in the queue bubbles
            if (self.queuable && self.type != self.stack.next.type) {
                self.log('queue ' + self.type);
                self.stack.queue.push([self, args]);
                return true;
            }
        }

        es = self.stack || {
           // id of the first event in the stack
           id: self.id,
           next: self,
           silent: self.silent,
           stopped: 0,
           prevented: 0,
           bubbling: null,
           type: self.type,
           // defaultFnQueue: new Y.Queue(),
           afterQueue: new Y.Queue(),
           defaultTargetOnly: self.defaultTargetOnly,
           queue: []
        };

        subs = self.getSubs();

        self.stopped = (self.type !== es.type) ? 0 : es.stopped;
        self.prevented = (self.type !== es.type) ? 0 : es.prevented;

        self.target = self.target || host;

        events = new Y.EventTarget({
            fireOnce: true,
            context: host
        });

        self.events = events;

        if (self.preventedFn) {
            events.on('prevented', self.preventedFn);
        }

        if (self.stoppedFn) {
            events.on('stopped', self.stoppedFn);
        }

        self.currentTarget = host;

        self.details = args.slice(); // original arguments in the details

        // self.log("Firing " + self  + ", " + "args: " + args);
        self.log("Firing " + self.type);

        self._facade = null; // kill facade to eliminate stale properties

        ef = self._getFacade(args);

        if (Y.Lang.isObject(args[0])) {
            args[0] = ef;
        } else {
            args.unshift(ef);
        }

        // if (subCount) {
        if (subs[0]) {
            // self._procSubs(Y.merge(self.subscribers), args, ef);
            self._procSubs(subs[0], args, ef);
        }

        // bubble if this is hosted in an event target and propagation has not been stopped
        if (self.bubbles && host.bubble && !self.stopped) {

            oldbubble = es.bubbling;

            // self.bubbling = true;
            es.bubbling = self.type;

            // if (host !== ef.target || es.type != self.type) {
            if (es.type != self.type) {
                es.stopped = 0;
                es.prevented = 0;
            }

            ret = host.bubble(self, args, null, es);

            self.stopped = Math.max(self.stopped, es.stopped);
            self.prevented = Math.max(self.prevented, es.prevented);

            // self.bubbling = false;
            es.bubbling = oldbubble;

        }

        if (self.defaultFn &&
            !self.prevented &&
            ((!self.defaultTargetOnly && !es.defaultTargetOnly) || host === ef.target)) {

            self.defaultFn.apply(host, args);
        }

        // broadcast listeners are fired as discreet events on the
        // YUI instance and potentially the YUI global.
        self._broadcast(args);

        // Queue the after
        if (subs[1] && !self.prevented && self.stopped < 2) {
            if (es.id === self.id || self.type != host._yuievt.bubbling) {
                self._procSubs(subs[1], args, ef);
                while ((next = es.afterQueue.last())) {
                    next();
                }
            } else {
                postponed = subs[1];
                if (es.execDefaultCnt) {
                    postponed = Y.merge(postponed);
                    Y.each(postponed, function(s) {
                        s.postponed = true;
                    });
                }

                es.afterQueue.add(function() {
                    self._procSubs(postponed, args, ef);
                });
            }
        }

        self.target = null;

        if (es.id === self.id) {
            queue = es.queue;

            while (queue.length) {
                q = queue.pop();
                ce = q[0];
                // set up stack to allow the next item to be processed
                es.next = ce;
                ce.fire.apply(ce, q[1]);
            }

            self.stack = null;
        }

        ret = !(self.stopped);

        if (self.type != host._yuievt.bubbling) {
            es.stopped = 0;
            es.prevented = 0;
            self.stopped = 0;
            self.prevented = 0;
        }

        return ret;
    };

    CEProto._getFacade = function() {

        var ef = this._facade, o, o2,
        args = this.details;

        if (!ef) {
            ef = new Y.EventFacade(this, this.currentTarget);
        }

        // if the first argument is an object literal, apply the
        // properties to the event facade
        o = args && args[0];

        if (Y.Lang.isObject(o, true)) {

            o2 = {};

            // protect the event facade properties
            Y.mix(o2, ef, true, FACADE_KEYS);

            // mix the data
            Y.mix(ef, o, true);

            // restore ef
            Y.mix(ef, o2, true, FACADE_KEYS);

            // Allow the event type to be faked
            // http://yuilibrary.com/projects/yui3/ticket/2528376
            ef.type = o.type || ef.type;
        }

        // update the details field with the arguments
        // ef.type = this.type;
        ef.details = this.details;

        // use the original target when the event bubbled to this target
        ef.target = this.originalTarget || this.target;

        ef.currentTarget = this.currentTarget;
        ef.stopped = 0;
        ef.prevented = 0;

        this._facade = ef;

        return this._facade;
    };

    /**
     * Stop propagation to bubble targets
     * @for CustomEvent
     * @method stopPropagation
     */
    CEProto.stopPropagation = function() {
        this.stopped = 1;
        if (this.stack) {
            this.stack.stopped = 1;
        }
        this.events.fire('stopped', this);
    };

    /**
     * Stops propagation to bubble targets, and prevents any remaining
     * subscribers on the current target from executing.
     * @method stopImmediatePropagation
     */
    CEProto.stopImmediatePropagation = function() {
        this.stopped = 2;
        if (this.stack) {
            this.stack.stopped = 2;
        }
        this.events.fire('stopped', this);
    };

    /**
     * Prevents the execution of this event's defaultFn
     * @method preventDefault
     */
    CEProto.preventDefault = function() {
        if (this.preventable) {
            this.prevented = 1;
            if (this.stack) {
                this.stack.prevented = 1;
            }
            this.events.fire('prevented', this);
        }
    };

    /**
     * Stops the event propagation and prevents the default
     * event behavior.
     * @method halt
     * @param immediate {boolean} if true additional listeners
     * on the current target will not be executed
     */
    CEProto.halt = function(immediate) {
        if (immediate) {
            this.stopImmediatePropagation();
        } else {
            this.stopPropagation();
        }
        this.preventDefault();
    };

    /**
     * Registers another EventTarget as a bubble target.  Bubble order
     * is determined by the order registered.  Multiple targets can
     * be specified.
     *
     * Events can only bubble if emitFacade is true.
     *
     * Included in the event-custom-complex submodule.
     *
     * @method addTarget
     * @param o {EventTarget} the target to add
     * @for EventTarget
     */
    ETProto.addTarget = function(o) {
        this._yuievt.targets[Y.stamp(o)] = o;
        this._yuievt.hasTargets = true;
    };

    /**
     * Returns an array of bubble targets for this object.
     * @method getTargets
     * @return EventTarget[]
     */
    ETProto.getTargets = function() {
        return Y.Object.values(this._yuievt.targets);
    };

    /**
     * Removes a bubble target
     * @method removeTarget
     * @param o {EventTarget} the target to remove
     * @for EventTarget
     */
    ETProto.removeTarget = function(o) {
        delete this._yuievt.targets[Y.stamp(o)];
    };

    /**
     * Propagate an event.  Requires the event-custom-complex module.
     * @method bubble
     * @param evt {CustomEvent} the custom event to propagate
     * @return {boolean} the aggregated return value from Event.Custom.fire
     * @for EventTarget
     */
    ETProto.bubble = function(evt, args, target, es) {

        var targs = this._yuievt.targets, ret = true,
            t, type = evt && evt.type, ce, i, bc, ce2,
            originalTarget = target || (evt && evt.target) || this,
            oldbubble;

        if (!evt || ((!evt.stopped) && targs)) {

            // Y.log('Bubbling ' + evt.type);
            for (i in targs) {
                if (targs.hasOwnProperty(i)) {
                    t = targs[i];
                    ce = t.getEvent(type, true);
                    ce2 = t.getSibling(type, ce);

                    if (ce2 && !ce) {
                        ce = t.publish(type);
                    }

                    oldbubble = t._yuievt.bubbling;
                    t._yuievt.bubbling = type;

                    // if this event was not published on the bubble target,
                    // continue propagating the event.
                    if (!ce) {
                        if (t._yuievt.hasTargets) {
                            t.bubble(evt, args, originalTarget, es);
                        }
                    } else {

                        ce.sibling = ce2;

                        // set the original target to that the target payload on the
                        // facade is correct.
                        ce.target = originalTarget;
                        ce.originalTarget = originalTarget;
                        ce.currentTarget = t;
                        bc = ce.broadcast;
                        ce.broadcast = false;

                        // default publish may not have emitFacade true -- that
                        // shouldn't be what the implementer meant to do
                        ce.emitFacade = true;

                        ce.stack = es;

                        ret = ret && ce.fire.apply(ce, args || evt.details || []);
                        ce.broadcast = bc;
                        ce.originalTarget = null;

                        // stopPropagation() was called
                        if (ce.stopped) {
                            break;
                        }
                    }

                    t._yuievt.bubbling = oldbubble;
                }
            }
        }

        return ret;
    };

    FACADE = new Y.EventFacade();
    FACADE_KEYS = Y.Object.keys(FACADE);

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