javascript - 有没有办法检测可观察对象的嵌套结构的任何元素是否已更改？

Question

是否有一个发射器可以在 viewModel.data() 的任何可观察元素发生更改时触发，或者我是否需要循环并订阅每个独立的可观察元素？

data: ko.observable([
      {
        name: "Chart Position",
        fields: ko.observableArray([
          {name: "marginBottom", type: "percOrNumber", value: ko.observable(), valueType: ko.observable()},
          {name: "marginLeft", type: "percOrNumber", value: ko.observable(), valueType: ko.observable()},
          {name: "marginRight", type: "percOrNumber", value: ko.observable(), valueType: ko.observable()},
          {name: "marginTop", type: "percOrNumber", value: ko.observable(), valueType: ko.observable()}
        ])
      }
    ]),

Answer 1

您可以使用计算的可观察量同时“订阅”多个可观察量。任何在计算的可观察量的评估中访问其值的可观察量都将成为依赖项。

所以，你可以这样做:

ko.computed(function() {
    this.one();  //just accessing the value for a dependency
    this.two();  //doesn't matter if we actually use the value
    this.three();

    //run some code here or if you have a reference to this computed observable, then you can even do a manual subscription against it.
}, vm);

如果您想订阅某个对象图中的所有可观察量，那么一个简单的方法就是使用ko.toJS。在您的示例中，您可能想要执行以下操作:

ko.computed(function() {
   ko.toJS(vm.data);  //will create dependencies on all observables inside "data"

   //run some code
}, vm.data);