Setup Nest and Firebase Functions

Nest + Firebase Functions

What is Nest?

Nest (NestJS) is a framework for building efficient, scalable Node.js server-side applications. It uses progressive JavaScript, is built with and fully supports TypeScript (yet still enables developers to code in pure JavaScript) and combines elements of OOP (Object Oriented Programming), FP (Functional Programming), and FRP (Functional Reactive Programming)

What is Firebase Functions?

Cloud Functions for Firebase is a serverless framework that lets you automatically run backend code in response to events triggered by Firebase features and HTTPS requests. Your JavaScript or TypeScript code is stored in Google’s cloud and runs in a managed environment. There’s no need to manage and scale your own servers.

How to mix Nest and Firebase Functions in a new project

Step 1: Create a nest project
Install nest cli and create a new project, in the steps choose your favorite package manager, I use npm for the rest of this article.

npm i -g @nestjs/cli
nest new my-awesome-project

then run

cd my-awesome-project
npm run start:dev

Running Nest for the first time

To make sure if everything is working till here, open a browser and open this URL http://localhost:3000 then you should see “Hello World!” in your browser.

Your project folder structure will look like this

Project structure after creating nest application

Step 2: Add Firebase Functions

install firebase tools and init the functions and follow the steps.

npm i -g firebase-tools
firebase init functions

Step 3: Get rid of functions folder

By running above command a new folder called functions will be added to the project.
Delete the functions folder

rm -rf functions

Step 4: Install dependencies

Now you need to install some packages by running

npm i firebase-admin firebase-functions express @nestjs/platform-express

and

npm i firebase-functions-test npm-run-all --save-dev

Step 5: Update firebase.json file

Find firebase.json file and update it like below

{
  "functions": {
     "source": "."
  }
}

Step 6: Update package.json

Open package.json and add below lines to it

"main": "dist/main.js",
"engines": {
  "node": "12"
},

update scripts section to below

"scripts": {
  "prenest:build": "rimraf dist",
  "start": "npm-run-all --parallel nest:start:dev fb:serve",
  "deploy": "npm-run-all nest:build fb:deploy",
  "nest:build": "nest build",
  "nest:start": "nest start",
  "nest:start:dev": "nest start --watch",
  "nest:start:debug": "nest start --debug --watch",
  "nest:start:prod": "node dist/main",
  "fb:build": "tsc",
  "fb:serve": "firebase serve --only functions",
  "fb:shell": "firebase functions:shell",
  "fb:start": "npm run fb:shell",
  "fb:deploy": "firebase deploy --only functions",
  "fb:logs": "firebase functions:log",
  "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
  "test": "jest",
  "test:watch": "jest --watch",
  "test:cov": "jest --coverage",
  "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
  "test:e2e": "jest --config ./test/jest-e2e.json"
},

Essentially what we are doing here is to rename existing nest commands to nest:xxx and adding some fb:xxx command, and running both nest:start:dev and fb:serve in parallel by using npm-run-all

Step 7: Update main.ts

Open main.ts file from src folder, and update it to below

import {NestFactory} from '@nestjs/core';
import {ExpressAdapter, NestExpressApplication} from '@nestjs/platform-express';
import * as express from 'express';
import * as functions from 'firebase-functions';
import {AppModule} from './app.module';
const server: express.Express = express();
export const createNestServer = async (expressInstance: express.Express) => {
  const adapter = new ExpressAdapter(expressInstance);
  const app = await NestFactory.create<NestExpressApplication>(
    AppModule, adapter, {},
  );
  app.enableCors();
  return app.init();
};
createNestServer(server)
  .then(v => console.log('Nest Ready'))
  .catch(err => console.error('Nest broken', err));
export const api: functions.HttpsFunction = functions.https.onRequest(server);

Step 8: Run the project

Run the project by

npm start

Your project should be running and you will see something like below

Running the project

To check if everything is working till now, find your URL as I highlighted in above picture and paste it to a new browser tab, you should see “Hello World!” again.

Step 9: Confirm Watch mode is working

While your project is running, open app.service.ts in src folder, and change return 'Hello World!'; to below and save.

return 'Together we will beat COVID-19'; 

Now refresh your browser, and you should see the changes without rebuilding the project manually.

Step 10: deploy to firebase

Run npm run deploy and you will see the output as below

Deploy nest to firebase functions

Step 11: Confirm the deployment works

Now open your project in firebase console and navigate to Functions menu, you should see the api function deployed as below

Deployed nestjs as firebase function

Now copy the URL and paste to a new browser. You should see “Together we will beat COVID-19” and it means you did an awesome job.

Final Project Folder Structure

NestJs + Firebase Functions final project structure

Full Code

Full code is available at https://github.com/RezaRahmati/nest-firebase-function-seed