A small Firebase project demonstrating how to fetch all the subcollections of a Firestore document.

The project is composed of:

• A Cloud Function that fetches the subcollections of a Document;
• A simple HTML page that demonstrates how it works from a web client.

It demonstrates the approach presented in the following article: https://medium.com/firebase-tips-tricks/how-to-list-all-subcollections-of-a-cloud-firestore-document-17f2bb80a166

• Clone the project $ git clone https://github.com/rtarnec/firestore-get-document-subcollections.git
• Install the packages locally by doing $ npm install in the functions directory
• From the project root directory, list your existing Firebase projects ($ firebase projects:list)
• Choose, from the list, the Firebase project you want to use for deployment (If you don't have any Firebase project -or you want to use a new project-, create one in the Firebase console https://console.firebase.google.com/, and re-do $ firebase projects:list)
• IMPORTANT Adapt in the public/index.html file, the Firebase config object with your own project config. See https://firebase.google.com/docs/web/setup#config-object.
• Deploy the project by doing $ firebase deploy

After deployment to Firebase, open the root url of the project (https://your-project-id.firebaseapp.com) with your preferred browser.

Enter a document path in the dedicated field and click the button "Get Subcollections":

• If the document has one or more subcollections the page will display their list and fetch each document of each subcollection.
• If the document at the path does not exist or if it does not have any subcollection, the Cloud Function will return an empty array.