未处理的Promise拒绝：push.on不是一个函数

我正在使用Ionic 2.

I am using Ionic 2.

我在尝试设置推送通知时遇到此Typescrpt 错误。我已从教程中复制了此示例代码，因此可以预期它可以正常工作。我一定有点不对劲。任何想法请：

I get this Typescrpt error when trying to set up Push Notifications. I have copied this sample code from a tutorial, so would have expected it to work. I must have something wrong. Any ideas please:

Unhandled Promise rejection: push.on is not a function ; Zone: angular ; Task: Promise.then ; Value:
TypeError: push.on is not a function


push.on('registration', function (data) {

typescript

import { Push } from 'ionic-native';

。
。

  pushNotifications(): void {

    var push = Push.init({
      android: {
        vibrate: true,
        sound: true,
        senderID: "xxxxxxxxxxxxxxxxxxx"
      },
      ios: {
        alert: "true",
        badge: true,
        sound: 'false'
      },
      windows: {}
    });

    push.on('registration', (data) => {
      console.log(data.registrationId);
      alert(data.registrationId.toString());
    });
    push.on('notification', (data) => {
      console.log(data);
      alert("Hi, Am a push notification");
    });
    push.on('error', (e) => {
      console.log(e.message);
    });

  }