Here\'s the code I\'m using to send a verification email (taken from the official docs)
var user = firebase.auth().currentUser;
user.sendEmailVerification().the
firebaser here
There is no client-side callback that triggers when the user clicks the verification link.
We've seen a feature request to trigger Cloud Functions when a user verifies their email address, but no updates on whether/when that will come. (Also see: Cloud Functions for Firebase - action on email verified)
The best I can think of now is to call User.reload() occasionally to get the updated properties.