实例化时ko.computed不触发功能 [英] ko.computed do not fire function upon instantiating

问题描述

有一种在实例化ko.computed时不触发该功能的方法

Hi is there a way to not fire the function when instantiating a ko.computed

示例是

我有这个ko.computing

i have this ko.computed

ko.computed(function(){ alert(this.Test); } , this);

所以基本上，如果我实例化此计算，这将触发在那里定义的函数 有没有办法在实例化时不触发它?并且仅在依赖项更改时才触发它?

so basically if i instantiated this computed this will fire the function defined there is there a way not to fire it upon instantiation? and only fire it when dependency change?

推荐答案

您需要设置 deferEvaluation选项:

You need to set the deferEvaluation option:

deferEvaluation-可选.如果此选项为true，则在某些实际尝试访问其值或手动订阅该值之前，将不会计算已计算的observable的值.默认情况下，计算的可观察对象的值会在创建过程中立即确定.

deferEvaluation — Optional. If this option is true, then the value of the computed observable will not be evaluated until something actually attempts to access its value or manually subscribes to it. By default, a computed observable has its value determined immediately during creation.

ko.computed(function(){ alert(this.Test); } , this, { deferEvaluation: true });

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