database.js

const functions = require('firebase-functions');
const admin = require('firebase-admin');
const uuid = require('uuid/v4');

admin.initializeApp(functions.config().firebase);
const collection = admin.firestore().collection('all');

module.exports = {
  async create(data) {
    const id = uuid();

    await collection.doc(id).create(data);

    return id;
  },

  async read(id) {
    const docRef = await collection.doc(id).get();

    return docRef.exists ? docRef.data() : undefined;
  },

  async update(id, data) {
    // Update must fail if the specified item does not already exist
    const docRef = await collection.doc(id).get();

    if (!docRef.exists) return false;

    await collection.doc(id).set(data);

    return true;
  },

  async delete(id) {
    return await collection.doc(id).delete();
  }
};