Firebase getToken() TypeError: Cannot read property

Question

I\'m trying to get the token of my currently signed in user of my website. However, javascript cannot get the value for me. I think there are 2 problems here:

Answer 1

According to the documentation of firebase.User:getIdToken():

Returns a JWT token used to identify the user to a Firebase service.

Returns the current token if it has not expired, otherwise this will refresh the token and return a new one.

The method returns a promise, since it may require a round-trip to the Firebase servers in case the token has expired:

Auth.currentUser.getIdToken().then(data => console.log(data))

Or in more classic JavaScript:

Auth.currentUser.getIdToken().then(function(data) {
    console.log(data)
});

Log output:

ey...biPA

Update: to ensure that the user is signed in before getting the token, run the above code in an onAuthStateChanged listener:

firebase.auth().onAuthStateChanged(function(user) {
  if (user) {
    user.getIdToken().then(function(data) {
      console.log(data)
    });
  }
});