Firestore functions listCollections() only returning empty array

Here is my database...

I have the following code in firebase functions...

const functions = require('firebase-functions');
const admin  = require('firebase-admin');

admin.initializeApp();
const db = admin.firestore();

exports.getCollections = functions.https.onCall(async (data, context) => {

    const path = admin.firestore().collection('BusinessName').doc('employee');
    const collections = await path.listCollections();

    collections.forEach(collection => {
      console.log('Found subcollection with id:', collection.id);
    });

    return({ collections: collections })

});

And the front end code...

    let buttonClick = () => {
        let getCollections = firebase.functions().httpsCallable('getCollections');
        getCollections().then((res) => {
            console.log(res);
        })
    }

There is two subcollections in this path. This function should return an array with the two test collections seen in the above image. However, it only returns an empty array.

and in the functions log...

I've tired different paths with different database structures, but the return is always an empty array. There must be something wrong with the node.js function, but it's right from firebase's docs. What do you think...?