还有其他方法可以观察Google Polymer 1.0中对象的子属性的变化吗？

Question

I've tried the deep path observation examples on the Google Polymer site but it does not work for my case. The sub-property I want to observe is an array that gets changed when I go to a different hash url. The problem is I'm using a library that handles that change so it doesn't use polymer's "push, pop, shift and splice" and without that, Polymer won't recognize the array mutation. Any ideas would be greatly appreciated!

Answer 1

I had what I think is a similar problem when trying to be notified of changes to an array in a computed property.

In my case I wanted to know when it's children were modified so that I could recompute something else with the changed children. Here's a snippet of working code from a polymer element:

properties: {
    choices: {
        type: Array,
        notify: true,
        value: []
    },
    choicesTransposed: {
        type: Array,
        notify: true,
        computed: '_transposeChoices(choices.*)'
    }
},

_transposeChoices: function(change) {
    var choices = change.base;
    // do something with choices
}

Initially I had _transposeChoices(choices) but this was never called when choices children were modified. Changing that to _transposeChoices(choices.*) and then using change.base in the computing function is what got things working for me.

Answer 2

您可以始终使用observe-js观察对象，并通过自定义事件与Polymer进行交互。