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Copyright (c) 2010, Yahoo! Inc. All rights reserved.
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Code licensed under the BSD License:
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http://developer.yahoo.com/yui/license.html
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YUI.add('history-base', function(Y) {
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* Provides browser history management functionality using a simple
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* add/replace/get paradigm. This can be used to ensure that the browser's back
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* and forward buttons work as the user expects and to provide bookmarkable URLs
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* that return the user to the current application state, even in an Ajax
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* application that doesn't perform full-page refreshes.
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* Provides global state management backed by an object, but with no browser
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* history integration. For actual browser history integration and back/forward
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* support, use the history-html5 or history-hash modules.
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* @submodule history-base
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* @param {Object} config (optional) configuration object, which may contain
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* zero or more of the following properties:
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* <dt>initialState (Object)</dt>
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* Initial state to set, as an object hash of key/value pairs. This will be
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* merged into the current global state.
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GlobalEnv = YUI.namespace('Env.History'),
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docMode = doc.documentMode,
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DEFAULT_OPTIONS = {merge: true},
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EVT_CHANGE = 'change',
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SRC_REPLACE = 'replace';
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function HistoryBase() {
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this._init.apply(this, arguments);
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Y.augment(HistoryBase, Y.EventTarget, null, null, {
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if (!GlobalEnv._state) {
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GlobalEnv._state = {};
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// -- Private Methods ----------------------------------------------------------
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* Returns <code>true</code> if <i>value</i> is a simple object and not a
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* function or an array.
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* @method _isSimpleObject
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* @param {mixed} value
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function _isSimpleObject(value) {
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return Lang.type(value) === 'object';
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// -- Public Static Properties -------------------------------------------------
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* Name of this component.
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HistoryBase.NAME = 'historyBase';
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* Constant used to identify state changes originating from the
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* <code>add()</code> method.
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HistoryBase.SRC_ADD = SRC_ADD;
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* Constant used to identify state changes originating from the
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* <code>replace()</code> method.
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* @property SRC_REPLACE
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HistoryBase.SRC_REPLACE = SRC_REPLACE;
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* Whether or not this browser supports the HTML5 History API.
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// All HTML5-capable browsers except Gecko 2+ (Firefox 4+) correctly return
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// true for 'onpopstate' in win. In order to support Gecko 2, we fall back to a
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// UA sniff for now. (current as of Firefox 4.0b2)
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HistoryBase.html5 = !!(win.history && win.history.pushState &&
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win.history.replaceState && ('onpopstate' in win || Y.UA.gecko >= 2));
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* Whether or not this browser supports the <code>window.onhashchange</code>
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* event natively. Note that even if this is <code>true</code>, you may
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* still want to use HistoryHash's synthetic <code>hashchange</code> event
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* since it normalizes implementation differences and fixes spec violations
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* across various browsers.
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* @property nativeHashChange
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// Most browsers that support hashchange expose it on the window. Opera 10.6+
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// exposes it on the document (but you can still attach to it on the window).
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// IE8 supports the hashchange event, but only in IE8 Standards
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// Mode. However, IE8 in IE7 compatibility mode still defines the
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// event but never fires it, so we can't just detect the event. We also can't
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// just UA sniff for IE8, since other browsers support this event as well.
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HistoryBase.nativeHashChange = ('onhashchange' in win || 'onhashchange' in doc) &&
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(!docMode || docMode > 7);
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Y.mix(HistoryBase.prototype, {
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// -- Initialization -------------------------------------------------------
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* Initializes this HistoryBase instance. This method is called by the
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* @param {Object} config configuration object
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_init: function (config) {
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* Configuration object provided by the user on instantiation, or an
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* empty object if one wasn't provided.
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config = this._config = config || {};
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* Resolved initial state: a merge of the user-supplied initial state
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* (if any) and any initial state provided by a subclass. This may
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* differ from <code>_config.initialState</code>. If neither the config
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* nor a subclass supplies an initial state, this property will be
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* @property _initialState
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initialState = this._initialState = this._initialState ||
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config.initialState || null;
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* Fired when the state changes. To be notified of all state changes
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* regardless of the History or YUI instance that generated them,
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* subscribe to this event on <code>Y.Global</code>. If you would rather
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* be notified only about changes generated by this specific History
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* instance, subscribe to this event on the instance.
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* @event history:change
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* @param {EventFacade} e Event facade with the following additional
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* <dt>changed (Object)</dt>
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* Object hash of state items that have been added or changed. The
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* key is the item key, and the value is an object containing
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* <code>newVal</code> and <code>prevVal</code> properties
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* representing the values of the item both before and after the
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* change. If the item was newly added, <code>prevVal</code> will be
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* <code>undefined</code>.
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* <dt>newVal (Object)</dt>
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* Object hash of key/value pairs of all state items after the
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* <dt>prevVal (Object)</dt>
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* Object hash of key/value pairs of all state items before the
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* <dt>removed (Object)</dt>
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* Object hash of key/value pairs of state items that have been
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* removed. Values are the old values prior to removal.
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* <dt>src (String)</dt>
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* The source of the event. This can be used to selectively ignore
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* events generated by certain sources.
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this.publish(EVT_CHANGE, {
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defaultFn: this._defChangeFn
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// If initialState was provided, merge it into the current state.
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this.add(initialState);
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// -- Public Methods -------------------------------------------------------
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* Adds a state entry with new values for the specified keys. By default,
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* the new state will be merged into the existing state, and new values will
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* override existing values. Specifying a <code>null</code> or
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* <code>undefined</code> value will cause that key to be removed from the
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* @param {Object} state Object hash of key/value pairs.
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* @param {Object} options (optional) Zero or more of the following options:
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* <dt>merge (Boolean)</dt>
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* If <code>true</code> (the default), the new state will be merged
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* into the existing state. New values will override existing values,
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* and <code>null</code> or <code>undefined</code> values will be
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* removed from the state.
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* If <code>false</code>, the existing state will be discarded as a
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* whole and the new state will take its place.
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var args = YArray(arguments, 0, true);
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args.unshift(SRC_ADD);
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return this._change.apply(this, args);
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* Adds a state entry with a new value for a single key. By default, the new
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* value will be merged into the existing state values, and will override an
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* existing value with the same key if there is one. Specifying a
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* <code>null</code> or <code>undefined</code> value will cause the key to
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* be removed from the new state entry.
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* @param {String} key State parameter key.
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* @param {String} value New value.
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* @param {Object} options (optional) Zero or more options. See
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* <code>add()</code> for a list of supported options.
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addValue: function (key, value, options) {
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return this._change(SRC_ADD, state, options);
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* Returns the current value of the state parameter specified by <i>key</i>,
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* or an object hash of key/value pairs for all current state parameters if
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* no key is specified.
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* @param {String} key (optional) State parameter key.
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* @return {Object|String} Value of the specified state parameter, or an
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* object hash of key/value pairs for all current state parameters.
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get: function (key) {
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var state = GlobalEnv._state,
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isObject = _isSimpleObject(state);
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return isObject && Obj.owns(state, key) ? state[key] : undefined;
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return isObject ? Y.mix({}, state, true) : state; // mix provides a fast shallow clone.
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* Same as <code>add()</code> except that a new browser history entry will
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* not be created. Instead, the current history entry will be replaced with
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* @param {Object} state Object hash of key/value pairs.
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* @param {Object} options (optional) Zero or more options. See
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* <code>add()</code> for a list of supported options.
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replace: function () {
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var args = YArray(arguments, 0, true);
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args.unshift(SRC_REPLACE);
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return this._change.apply(this, args);
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* Same as <code>addValue()</code> except that a new browser history entry
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* will not be created. Instead, the current history entry will be replaced
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* with the new state.
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* @method replaceValue
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* @param {String} key State parameter key.
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* @param {String} value New value.
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* @param {Object} options (optional) Zero or more options. See
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* <code>add()</code> for a list of supported options.
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replaceValue: function (key, value, options) {
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return this._change(SRC_REPLACE, state, options);
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// -- Protected Methods ----------------------------------------------------
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* Changes the state. This method provides a common implementation shared by
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* the public methods for changing state.
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* @param {String} src Source of the change, for inclusion in event facades
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* to facilitate filtering.
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* @param {Object} state Object hash of key/value pairs.
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* @param {Object} options (optional) Zero or more options. See
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* <code>add()</code> for a list of supported options.
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_change: function (src, state, options) {
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options = options ? Y.merge(DEFAULT_OPTIONS, options) : DEFAULT_OPTIONS;
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if (options.merge && _isSimpleObject(state) &&
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_isSimpleObject(GlobalEnv._state)) {
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state = Y.merge(GlobalEnv._state, state);
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this._resolveChanges(src, state, options);
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* Called by _resolveChanges() when the state has changed. This method takes
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* care of actually firing the necessary events.
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* @method _fireEvents
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* @param {String} src Source of the changes, for inclusion in event facades
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* to facilitate filtering.
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* @param {Object} changes Resolved changes.
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* @param {Object} options Zero or more options. See <code>add()</code> for
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* a list of supported options.
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_fireEvents: function (src, changes, options) {
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// Fire the global change event.
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this.fire(EVT_CHANGE, {
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changed : changes.changed,
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newVal : changes.newState,
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prevVal : changes.prevState,
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removed : changes.removed,
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// Fire change/remove events for individual items.
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Obj.each(changes.changed, function (value, key) {
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this._fireChangeEvent(src, key, value);
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Obj.each(changes.removed, function (value, key) {
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this._fireRemoveEvent(src, key, value);
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* Fires a dynamic "[key]Change" event.
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* @method _fireChangeEvent
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* @param {String} src source of the change, for inclusion in event facades
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* to facilitate filtering
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* @param {String} key key of the item that was changed
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* @param {Object} value object hash containing <i>newVal</i> and
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* <i>prevVal</i> properties for the changed item
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_fireChangeEvent: function (src, key, value) {
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* Dynamic event fired when an individual history item is added or
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* changed. The name of this event depends on the name of the key that
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* changed. To listen to change events for a key named "foo", subscribe
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* to the <code>fooChange</code> event; for a key named "bar", subscribe
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* to <code>barChange</code>, etc.
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* Key-specific events are only fired for instance-level changes; that
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* is, changes that were made via the same History instance on which the
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* event is subscribed. To be notified of changes made by other History
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* instances, subscribe to the global <code>history:change</code> event.
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* @param {EventFacade} e Event facade with the following additional
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* <dt>newVal (mixed)</dt>
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* The new value of the item after the change.
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* <dt>prevVal (mixed)</dt>
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* The previous value of the item before the change, or
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* <code>undefined</code> if the item was just added and has no
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* <dt>src (String)</dt>
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* The source of the event. This can be used to selectively ignore
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* events generated by certain sources.
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this.fire(key + 'Change', {
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newVal : value.newVal,
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prevVal: value.prevVal,
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* Fires a dynamic "[key]Remove" event.
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* @method _fireRemoveEvent
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* @param {String} src source of the change, for inclusion in event facades
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* to facilitate filtering
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* @param {String} key key of the item that was removed
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* @param {mixed} value value of the item prior to its removal
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_fireRemoveEvent: function (src, key, value) {
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* Dynamic event fired when an individual history item is removed. The
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* name of this event depends on the name of the key that was removed.
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* To listen to remove events for a key named "foo", subscribe to the
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* <code>fooRemove</code> event; for a key named "bar", subscribe to
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* <code>barRemove</code>, etc.
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* Key-specific events are only fired for instance-level changes; that
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* is, changes that were made via the same History instance on which the
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* event is subscribed. To be notified of changes made by other History
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* instances, subscribe to the global <code>history:change</code> event.
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* @param {EventFacade} e Event facade with the following additional
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* <dt>prevVal (mixed)</dt>
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* The value of the item before it was removed.
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* <dt>src (String)</dt>
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* The source of the event. This can be used to selectively ignore
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* events generated by certain sources.
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this.fire(key + 'Remove', {
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* Resolves the changes (if any) between <i>newState</i> and the current
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* state and fires appropriate events if things have changed.
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* @method _resolveChanges
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* @param {String} src source of the changes, for inclusion in event facades
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* to facilitate filtering
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* @param {Object} newState object hash of key/value pairs representing the
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* @param {Object} options Zero or more options. See <code>add()</code> for
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* a list of supported options.
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_resolveChanges: function (src, newState, options) {
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prevState = GlobalEnv._state,
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if (_isSimpleObject(newState) && _isSimpleObject(prevState)) {
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// Figure out what was added or changed.
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Obj.each(newState, function (newVal, key) {
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var prevVal = prevState[key];
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if (newVal !== prevVal) {
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// Figure out what was removed.
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Obj.each(prevState, function (prevVal, key) {
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if (!Obj.owns(newState, key) || newState[key] === null) {
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delete newState[key];
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removed[key] = prevVal;
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isChanged = newState !== prevState;
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this._fireEvents(src, {
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prevState: prevState,
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* Stores the specified state. Don't call this method directly; go through
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* _resolveChanges() to ensure that changes are resolved and all events are
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* @method _storeState
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* @param {String} src source of the changes
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* @param {Object} newState new state to store
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* @param {Object} options Zero or more options. See <code>add()</code> for
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* a list of supported options.
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_storeState: function (src, newState) {
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// Note: the src and options params aren't used here, but they are used
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GlobalEnv._state = newState || {};
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// -- Protected Event Handlers ---------------------------------------------
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* Default <code>history:change</code> event handler.
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* @method _defChangeFn
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* @param {EventFacade} e state change event facade
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_defChangeFn: function (e) {
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this._storeState(e.src, e.newVal, e._options);
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Y.HistoryBase = HistoryBase;
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}, '3.2.0' ,{requires:['event-custom-complex']});
added
removed
src-js/lazrjs/yui/history/history-base.js
