EXTJS7 自定义配置延迟初始化

config段中的自定义配置默认会在initConfig中被初始化，一般会在构造函数中调用initConfig。
使用lazy属性可以避免配置在initConfig时被初始化，延迟到被调用时初始化。(延迟触发apply、update)

样例

config: {
	configProp: 'prop',
	configPropLazy: {
		lazy: true,
		$value: 'configPropLazy'
	}
}

源码分析

初始化

Base.js

initConfig: function(instanceConfig) {
    var me = this,
        cfg = me.self.getConfigurator();

    me.initConfig = Ext.emptyFn; // ignore subsequent calls to initConfig
    me.initialConfig = instanceConfig || {};
    cfg.configure(me, instanceConfig);

    return me;
},

Configurator.js

configure: function(instance, instanceConfig) {
	...
	if (cfg && !cfg.lazy) {
	    --remaining;
	    // A proper "config" property so call the setter to set the value.
	    names = cfg.names;
	    getter = names.get;
	
	    // At this point the initGetter may have already been called and
	    // cleared if the getter was called from the applier or updater of a
	    // previously processed instance config. checking if the instance has
	    // its own getter ensures the setter does not get called twice.
	    if (instance.hasOwnProperty(getter)) {
	        instance[names.set](values[name]);
	
	        // The generated setter will remove the initGetter from the instance
	        // but the user may have provided their own setter so we have to do
	        // this here as well:
	        delete instance[names.get];
	    }
	}
	...
}

延迟初始化

Config.js

makeInitGetter: function() {
    var name = this.name,
        names = this.names,
        setName = names.set,
        getName = names.get,
        initializingName = names.initializing;

    return function() {
        var me = this;

        me[initializingName] = true;
        // Remove the initGetter from the instance now that the value has been set.
        delete me[getName];

        me[setName](me.config[name]);
        delete me[initializingName];

        return me[getName].apply(me, arguments);
    };
},