Firestore in Cloud Functions

function.js

const {Firestore} = require('@google-cloud/firestore');
const firestore = new Firestore();

exports.helloWorld = async (req, res) => {
  const document = firestore.doc('users/steren');
  const doc = await document.get();
  console.log('Read the document');

  res.status(200).send('Hey');
};