订阅相同的可观察对象，获取该可观察对象的先前值 [英] Get previous value of an observable in subscribe of same observable

问题描述

在剔除中，是否有可能在订阅中获得可观察值的当前值，然后再接收新值?

Is it possible in knockout to get the current value of an observable within a subscription to that observable, before it receives the new value?

示例:

this.myObservable = ko.observable();
this.myObservable.subscribe(function(newValue){
    //I'd like to get the previous value of 'myObservable' here before it's set to newValue
});

推荐答案

有一种方法可以像这样对before值进行订阅:

There is a way to do a subscription to the before value like this:

this.myObservable = ko.observable();
this.myObservable.subscribe(function(previousValue){
    //I'd like to get the previous value of 'myObservable' here before it's set to newValue
}, this, "beforeChange");

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