Uncaught (in promise) Error: GraphQL error: Cannot read property 'id' of null

Steps to reproduce:

1. Login as a new user (hasn’t entered their email yet)
2. Select a trip from the home page
3. Add trip to cart
4. Go to cart
5. Click Book All

It will explode with: Uncaught (in promise) Error: GraphQL error: Cannot read property ‘id’ of null.

Looking at the error more closely reveals that we are caching the guest user somewhere. The error comes back from

// src/datasources/user.js:35
const userId = this.context.user.id;
if (!userId) return;

This means the user context is null

[philohelp]

Same error here. Unable to execute the last part of the tutorial - on the server part. This is very disturbing when you want to learn a new piece of knowledge and you find yourself trying to solve a bug in a technology that by definition you don’t master yet.

[gdesjonqueres]

Surprisingly this issue is still opened. According to Apollo Client own documentation authentication token should be handled this way: https://stackoverflow.com/questions/58556687/react-apollo-how-to-set-authorization-header-when-user-logs-in

(See first solution by Abderrahim Soubai Elidrissi)