onstatechange firebase cant get stsTokenManager

var user = firebase.auth().currentUser;

if (user) {
  // User is signed in.
} else {
  // No user is signed in.
}

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

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