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);
};
},
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