Firebase tips

createUserWithEmailAndPassword.js.js

// Auth an user and create it instantly in users collection
firebase.auth().createUserWithEmailAndPassword(email, password)
  .then((userCredential) => {
    return firebase.firestore().collection('users').doc(userCredential.user.uid)
                    .set({
                        field1: 'my-field-value',
                        field2: 'my-field-value'
                      );
  })
  .then(() => {
      // user created
   })
  .catch((error) => {
    var errorCode = error.code;
    var errorMessage = error.message;
    // ..
  });