Ionic platform web client register push bug

I do

.run(function($ionicPlatform) {
$ionicPlatform.ready(function() {
var push = new Ionic.Push({
“debug”: true

push.register(function(token) {
  console.log("Device token:",token.token);
  push.saveToken(token);  // persist the token in the Ionic Platform


but I got this error.

Uncaught TypeError: t._getPushPlugin(…).init is not a function,, Line: 3

I remember previously it was working, but now I got that error. I’m using