Onesignal managing tags

Ionic Framework ionic-v3
1

Hi all,
I want to use Onesignal tags in order to send a push a subset of my users.

To register the user to receive the push notification, I use this code and it works successfully:

var notificationReceidedCallback = function (jsonData) {
        console.log(jsonData);
        console.log('notificationReceidedCallback: ' + JSON.stringify(jsonData));
      };

      var notificationOpenedCallback = function (jsonData) {
        console.log(jsonData);
        console.log('notificationOpenedCallback: ' + JSON.stringify(jsonData));
      };

      window["plugins"].OneSignal
        .startInit(FIREBASE_APP_ID, FIREBASE_SENDER_ID)
        //.InFocusDisplaying(OneSignal.OSInFocusDisplayOption.InAppAlert)
        .handleNotificationOpened(notificationOpenedCallback)
        .handleNotificationReceived(notificationReceidedCallback)
        .endInit();

I don’t understand How add the register to specific tag. I read the official documentation https://documentation.onesignal.com/docs/web-push-sdk#section–sendtags- but I have problem at runtime:

OneSignal.push(function() {

  OneSignal.sendTags({
    key: 'value',
    key2: 'value2',
  }).then(function(tagsSent) {
    // Callback called when tags have finished sending    
  });

});

In the console:

message: "Uncaught (in promise): TypeError: Cannot call method 'then' of undefined↵TypeError: Cannot call method 'then' of undefined↵    at MyApp.enablePush (http://localhost/build/main.js:2031:16)↵    at http://localhost/build/main.js:2090:31↵    at t.invoke (http://localhost/build/polyfills.js:3:14976)↵    at Object.zone._inner.zone._inner.fork.onInvoke (http://localhost/build/vendor.js:5396:33)↵    at t.invoke (http://localhost/build/polyfills.js:3:14916)↵    at r.run (http://localhost/build/polyfills.js:3:10143)↵    at http://localhost/build/polyfills.js:3:20242↵    at t.invokeTask (http://localhost/build/polyfills.js:3:15660)↵    at Object.zone._inner.zone._inner.fork.onInvokeTask (http://localhost/build/vendor.js:5387:33)↵    at t.invokeTask (http://localhost/build/polyfills.js:3:15581)"

Could you please support me?

Thanks in advance
Luca