Polymer.prototype.splice的行为不符合预期 [英] Polymer.prototype.splice don't behave as expected

问题描述

我正在使用Polymer的阵列突变方法进行阵列突变.

I'm doing array mutation with Polymer's array mutation methods.

  this.allRules = [{name: "abc", enabled: true}];     

  var item = this.allRules[index];
  item.name = "abcdxfdsa";
  item.enabled = enabled;

  // console log out [Object]
  console.log(this.allRules);
  this.splice('allRules', index, 1);
  // Instead of logging out [], it logs out [splices: Object]
  console.log(this.allRules);
  this.push('allRules', item);
  // It logs out [Object, splices: Object]
  console.log(poly.allRules);

这很烦人.当我将this.allRules绑定到dom-repeat模板(例如下面的模板)中时，更新的绑定数据时，它将显示被拼接的项目，而不是新添加的项目.因此，在进行拼接和推送之后，我得到的不是"abcdxfdsa"，而是拼接前的值，而不是获得"abcdxfdsa"作为项目名称.这是指向示例dom-repeat数据绑定的链接. 聚合物dom-repeat如何通知阵列已更新

And the annoying thing is this. When I bind this.allRules into a dom-repeat template, such as the one below, when updated binded data, it shows the item that was spliced instead of the newly added item. So after a splice and a push, instead of getting "abcdxfdsa" as item name, I get abc, which is the value before splicing. Here is the link to a sample dom-repeat data binding. Polymer dom-repeat how to notify array updated

推荐答案

实际上应该从数组中删除该项目.它第二次以[splices: Object]身份登出，只是为了显示有关此数组的更多信息，因为它具有一个名为

Actually the item should be removed from the array. The second time it logs out as [splices: Object] just to show more info about this array, as it has a property called splices. If you run the same thing in Firefox you will still see [object] so I guess this is just a Chrome console helper thing.

要获取要更新的值，一种方法是将this.push调用包装在this.async方法内.

To get the value to be updated, one way is to wrap the this.push call inside a this.async method.

  this.async(function() {
    this.push('allRules', item);
    console.log(item);
    console.log(this.allRules[0].name);
    // returns 1, meaning it's filled with one item again
    console.log(this.allRules.length);
  });

看看这个 plunker 作为工作示例.

Have a look at this plunker for a working sample.

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