Dir structure:

├── public/
│   ├── index.html
│   └── js/
│       ├── init.js
│       ├── auth.js
│       └── app.js
│       
└── functions/
    └── index.js

Firebase console

GCP function logs

Firebase commands:

firebase deploy --only functions
firebase deploy --only functions:myfunc
firebase functions:log --only myfunc
firebase init hosting:github
firebase init emulator  
firebase emulators:start