The Google Developer Sheets API for Javascript has a great quickstart: https://developers.google.com/sheets/api/quickstart/js

My application is based on this and has been good for years. However, the quickstart uses gapi.auth2 which is to be deprecated.

Source: Migrate to Google Identity Services: https://developers.google.com/identity/oauth2/web/guides/migration-to-gis

This guide states that "if using the API Client Library, remove the deprecated gapi.auth2 module, its methods and objects, replacing them with Identity Services equivalents."

Does anyone have a similar quickstart, but which uses the new Google Identity Service?

I have attempted to follow the migration guide, however it's beyond my ability to create something that works.

Particularly difficult for me is the section that states: Previously, Google Sign-In helped you to manage user signed-in status using: .... You are responsible for managing sign-in state and user sessions to your web app.