ko.observableArray对关联数组的支持 [英] ko.observableArray support for associative arrays

问题描述

是否存在更好的(内置的)混合observableArray和关联数组的方法?

Is there a better (built in?) way to mix observableArray and associative arrays?

viewModel = {
    a: ko.observableArray(),
    a_assoc: {},
    add_item: function(i) {
        if (typeof this.a_assoc[i] == 'undefined') {
            this.a.push(i);
            this.a_assoc[i]=1;
        }
    }
}

viewModel.add_item('bla');

推荐答案

通常，您可以在淘汰赛中执行以下操作:

Typically, you would do something like this in Knockout:

var viewModel = {
    a: ko.observableArray(["a","b","c","d"]),
    add_item: function() {
       this.a.push("new" + this.a().length);   
    }
};

viewModel.a_assoc = ko.dependentObservable(function() {
    var result = {};
    ko.utils.arrayForEach(this.a(), function(item) {
       result[item] = 1;
    });
    return result;
}, viewModel);

因此，您有一个dependentObservable，它将数组映射到对象.请注意，每次更新原始数组时，都会重建对象.因此，它的效率不如您的帖子中的方法有效，但是除非您的对象很大，否则是否会导致性能问题值得怀疑.

So, you have a dependentObservable that maps your array to an object. Note that each time that the original array is updated, the object is rebuilt. So, it is less efficient than the method in your post, but unless your object is substantially big, it is doubtful that it would cause a performance issue.

此处提供示例: http://jsfiddle.net/rniemeyer/PgceN/

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