Trying to make use of the Server to Server OAuth flow defined here: https://developers.google.com/identity/protocols/OAuth2ServiceAccount
Since I'm running from a local dev environment, I've created a service account in GCP and downloaded the JSON file with the private key, but cannot find any Node.js code examples on how to: 1) load the json file 2) set delegated credentials (for G Suite domain-wide authorization)
Places I've looked (besides stackoverflow) are Google's git wiki for the node.js client library, which does talk about server to server auth, but seems to assume you're running from appengine or google cloud and don't need to load a key file: https://github.com/googleapis/google-api-nodejs-client#service-to-service-authentication
The Admin SDK Activities Reports API has a Node example, but it's using the web-based flow assuming a user is present: https://developers.google.com/admin-sdk/reports/v1/quickstart/nodejs
Buried deep in the Node.js samples is use of the Directory API, which does seem to take a keyfile as input, but when I try running locally it says getClient is not a constructor, and still this example doesn't show how to set the G Suite admin user for context (which is generally when a refresh token and access token are loaded into the app): https://github.com/googleapis/google-api-nodejs-client/blob/master/samples/directory_v1/group-delete.js
So... does anybody have an example of this? I really don't want to switch to a Python runtime but Google seems to have left out important examples on this topic.