Declare separate Firebase Cloud Functions and still use Express.js

Question

There are many examples of using Express for Firebase Cloud Functions.

In every example of I have found the code exposes the Express app as a single Cloud Function:<

Answer 1

Interesting discussion.

I choose the same approach : one "endpoint" (aka a root route like "/posts", "/users") == a dedicated cloud function (for the reason already evoked + it's more "µservice like" and it's what are "lambda functions" for me).

To be "DRY" all my function import an "express" generator. I configure my express instance in one place.

const express = () => {
  const express = require("express");
  const cors = require("cors")({ origin: true });
  const morgan = require("morgan");
  const helmet = require("helmet");

  const app = express();

  app.use(helmet());
  app.use(helmet.noCache());
  app.use(cors);
  app.use(morgan("combined"));

  return app;
};

module.exports = express;

My "hello" endpoint :

const app = require("./../../express")();

/**
 * /hello
 */

app.get("/", (req, res) => {
  return res.send("Hello World");
});

module.exports = app;

My index.js (main export) :

const helloApi = require("./api/hello");

const https = functions.region("europe-west1").https;

module.exports.hello = https.onRequest(helloApi);

Seems to work well for us :)