Cloud Functions auth onCreate trigger add user to firestore

Question

I am trying to add a user object to firestore when a user registers through google auth. here is my code:

export const accountCreate = functions.auth.user().onCreate(user => {
    console.log(user.data);
    admin.firestore().collection('users').doc(user.data.uid).set(user.data).then(writeResult => {
        console.log('User Created result:', writeResult);
        return;
    }).catch(err => {
        console.log(err);
        return;
    });
});

No luck, I just keep getting the error:

Error: Cannot encode type ([object Object]) to a Firestore Value at Function.encodeValue (/user_code/node_modules/firebase-admin/node_modules/@google-cloud/firestore/src/document.js:773:11)

I am not sure why this isn't working. Any Ideas? Thanks

Answer 1

user.data isn't a valid Cloud Firestore document, so Firestore is rejecting the write. Instead, you should set the specific fields you care about, e.g.:

export const accountCreate = functions.auth.user().onCreate(user => {
    console.log(user.data);
    userDoc = {'email' = user.data.email, 
               'displayName' = user.data.displayName}
    admin.firestore().collection('users').doc(user.data.uid)
    .set(userDoc).then(writeResult => {
        console.log('User Created result:', writeResult);
        return;
    }).catch(err => {
       console.log(err);
       return;
    });
});

Answer 2

Following from Dans answer, it's possible to just serialize the UserRecord and place everything into the document without having to think about what you:

A complete working example:

import * as functions from 'firebase-functions';

const admin = require('firebase-admin');

admin.initializeApp({
  databaseURL: 'https://challenges-f9f6b.firebaseio.com'
});

export const addUser = functions.auth.user().onCreate((user) => {
  return admin
    .firestore()
    .collection('users')
    .doc(user.uid)
    .set(JSON.parse(JSON.stringify(user)));
});