Vue异步加载组件 Vue异步加载about组件

Vue.component('about', {template: '<div>ABOUT PAGE</div>'}); 

<div id="app">
    <router-link to="/home">/home</router-link>
    <router-link to="/about">/about</router-link>
    <router-view></router-view>
  </div>
  <script src="static/js/vue.min.js"></script>
  <script src="static/js/vue-router.js"></script>
  <script>
    function load (componentName, path) {
      return new Promise(function (resolve, reject){
        var script = document.createElement('script');
        script.src = path;
        script.async = true;
        script.onload = function () {
          var component = Vue.component(componentName);
          if (component) {
            resolve(component);
          } else {
            reject();
          }
        }
        document.body.appendChild(script);
      });
    }
    var router = new VueRouter({
      routes: [{
        path: '/',
        redirect: '/home'
      }, {
        path: '/home',
        component: {
          template: '<div>HOME PAGE</div>'
        }
      },{
        path: '/about',
        component: function (resolve, reject) {
          load('about', 'static/js/business/about.js').then(resolve, reject);
        }
      }]
    });
    var app = new Vue({
      el: '#app',
      router: router
    });
  </script>