淘汰赛：从null开始observableArray

Question

Seems that in knockout 3.2.0 they changed the behavior of ObservableArrays. In knockout 2, if I did:

var array = ko.observableArray(null)
console.log(array())

It would return me null. The same thing on knockout 3.2.0 doesn't happen because the observable array instead of null is create as an empty array.

This is my case:

<div>
 <div class="spinner" data-bind="visible: comments() == null">
 <!-- ko foreach: comments -->
 ...
 <!-- /ko -->
</div>

I'd like to start showing in the comments div a spinner, and when the comments are populated, i'll hide the spinner and show the comments. I can't do data-bind="visible: comments().length == 0" because if the post has no comments, the comments array will have 0 length and the spinner will be shown forever.

How can I make this work?

Answer 1

This would work.

self.comments = ko.observableArray([]);

<!-- ko if: comments().length > 0 -->
Greater than zero // Show spinner
<!-- /ko -->
<!-- ko ifnot: comments().length > 0 -->
No greater than zero // No spinner needed
<!-- /ko -->

Let me know what you think.