add extjs 6.0.1 sources

[extjs.git] / extjs / packages / core / src / plugin / LazyItems.js

/**\r
 * This plugin defers the execution cost of the instantiation and initialization of child components of un-rendered items.\r
 *\r
 * For example, in a {@link Ext.tab.Panel#deferredRender deferredRender} {@link Ext.tab.Panel TabPanel}, the un-rendered tabs\r
 * do not have to incur the cost of instantiating and initializing their descendant components until render.\r
 *\r
 * This plugin allows that.\r
 *\r
 * Add the items to the plugin:\r
 *\r
 *     {\r
 *         xtype: 'tabpanel',\r
 *         items: [{\r
 *             title: 'Tab One',\r
 *             plugins: {\r
 *                 ptype: 'lazyitems',\r
 *                 items: [... tab child items...]\r
 *             }\r
 *         }, {\r
 *             title: 'Tab One',\r
 *             plugins: {\r
 *                 ptype: 'lazyitems',\r
 *                 items: [... tab child items...]\r
 *             }\r
 *         }]\r
 *     }\r
 *\r
 */\r
Ext.define('Ext.plugin.LazyItems', {\r
    extend: 'Ext.plugin.Abstract',\r
 \r
    alias: 'plugin.lazyitems',\r
 \r
    init: function(comp) {\r
        this.callParent(arguments);\r
 \r
        if (this.items) {\r
            // Eager instantiation means create the child items now\r
            if (this.eagerInstantiation) {\r
                this.items = comp.prepareItems(this.items);\r
            }\r
        }\r
 \r
        // We need to jump in right before the beforeRender call\r
        comp.beforeRender = Ext.Function.createInterceptor(comp.beforeRender, this.beforeComponentRender, this);\r
    },\r
 \r
    // Add the child items at the last possible moment.\r
    beforeComponentRender: function() {\r
        this.cmp.add(this.items);\r
 \r
        // Remove the interceptor\r
        this.cmp.beforeComponentRender = null;\r
    }\r
});\r