将某些observableArray对象属性转换为可观察对象 [英] Turn certain observableArray objects properties into observable

问题描述

假设我有这个相同类型对象的数组：

Say I have this array of same-type objects:

var people = [
    { status: 0, name: "name1"},
    { status: 1, name: "name2"}
];

我希望它不仅是observableArray，而且我还想要观察，例如，状态每个对象的属性。

and I want it not only to be observableArray, but also I want to observe ONLY, say, status property of each object.

想象一下，可能会添加或删除对象本身。任何这些对象的name属性都不会改变，所以我不需要观察名称，但每个对象的状态可能会被改变，因此让它可观察是很酷的。

Imagine that the objects themselves might be added or deleted. The name property of any of those objects is not going to change so I don't really need to observe the name but the status of every object might get changed, thus it'd be cool to make it observable.

是否可以使用一些很酷的黑客语法将其与knockout实用程序一起映射，或者我是否必须迭代每个对象并将其status属性映射到observable或者具有整个数组及其对象属性可观察？

Is it possible to map it with knockout utilities with some cool hack syntax or do I have to either iterate through every object and map its status property into observable or have the whole array and its objects properties observable?

推荐答案

你可以使用 ko.mapping.fromJS

var vm = ko.mapping.fromJS(people,{
    create: function(options){    
        return {
            status : ko.observable(options.data.status), // observable
            name: options.data.name, // non observable
        }
    }
});

现在vm是一个observableArray，它包含状态是可观察的对象，而name是常规属性。

Now vm is an observableArray that contains objects in which status is an obsevable and name is a regular property.

查看小提琴

@Patryk：

如果你有很多房产，你可以这样做并且你想只将一个转换为observable。

You could do that, if you have many properties and you want to convert only one into observable.

var o = ko.mapping.fromJS(people,{create: function(options){
    // clone item
    var item = ko.utils.extend(options.data, {});
    // replace status property by an observable 
    item.status = ko.observable(options.data.status);
    return item;
}});

查看更新的小提琴

您还可以使用观察，带有映射参数

You could also use observe with mapping parameter

var mapping = {
    create: function (options) {
        return ko.mapping.fromJS(options.data, {'observe': ["status"]});
    }
};
var o = ko.mapping.fromJS(people, mapping);

查看小提琴

我希望它有所帮助。

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