Polymer 1.x:使用 iron-input 格式化输入的数字

Polymer 1.x: Using iron-input to format numbers on input

In this jsBin, I format input numbers using commas。但是有没有一种方法可以使用 Polymer 元素(比如 <iron-input 来实现这一点,这样可以减少代码量并提供更适合平台的解决方案?

<!doctype html>
<head>
  <meta charset="utf-8">
  <base href="https://polygit.org/components/">
  <script src="webcomponentsjs/webcomponents-lite.min.js"></script>
  <link href="polymer/polymer.html" rel="import">
  <link href="paper-input/paper-input.html" rel="import">
  <script src="//cdnjs.cloudflare.com/ajax/libs/numeral.js/1.4.5/numeral.min.js"></script>
</head>
<body>

<dom-module id="x-element">

<template>
  <style></style>

<paper-input value="{{num}}"></paper-input>

</template>

<script>
  (function(){
    Polymer({
      is: "x-element",
      properties: {
        num: {
          type: String,
          observer: '_numChanged',
        },
      },
      attached: function() {
        this.numBeingChanged = false;
      },
      _numChanged: function(num) {
        console.log('num', num);
        if (!this.numBeingChanged) {
          this.numBeingChanged = true; //prevent recursion
          var x = num.replace(/\D/g,'')
          x = parseInt(x);
          console.log('x', x);
          this.set('num', numeral(x).format('0,0'));
          this.numBeingChanged = false;
        }
      }
    });
  })();
</script>

</dom-module>

<x-element></x-element>

</body>

似乎是 toLocalString()Number 原型上的工作: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toLocaleString