This is a short NodeJS & Firebase API Rest CRUD
You'll need to create a credentials.json file which will contain all the private information necessary to connect to your Firebase account and database.
To do that, create a Firebase account and project (https://firebase.google.com/). In this project, on the Firestore Database, create a new collection called "animals".
Then in project settings, go to service accounts and click on "generate a new private key". Download and rename the file as ".credentials.json".
You can now clone this repository and place your .credentials.json file inside the folder. Congratulations, you can now GET, PATCH, POST & DELETE animals in your firebase database !