How to setting up NestJS on Firebase Cloud

Option A - Point a Function to Nest

The first setup modifies the functions configuration to use the Nest **/dist** output, as opposed to the default functions directory. This option is ideal if you have an existing Nest app.

Step 1 - Create Nest App

nest generate app server

Step 2 - Add Functions

Add functions, then delete the automatically generated directory.

npm i -g firebase-tools
firebase init functions


rm -rf functions 

Now update the firebase config to point to the nest app.

 "functions": {
    "predeploy": [
      "npm --prefix \"$RESOURCE_DIR\" run build"
    ],
&nbsp; &nbsp; "source": "server" // <-- here
&nbsp; }
}

firebase.json

Step 3 - Install Dependencies

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

Step 4 - Update the package.json

Add the following lines to your package.json.

{
  // ...
  "main": "dist/index.js",
  "engines": {
    "node": "8"
  }
}

Step 5 - Export the Server

Create a new file named **src/index.ts** that creates an exress app and wraps it with Nest.

import { NestFactory } from '@nestjs/core';
import { ExpressAdapter } from '@nestjs/platform-express';
import { AppModule } from './app.module';
import * as express from 'express';
import * as functions from 'firebase-functions';

const server = express();

export const createNestServer = async (expressInstance) => {
  const app = await NestFactory.create(
    AppModule,
    new ExpressAdapter(expressInstance),
  );


  return app.init();
};

createNestServer(server)
    .then(v => console.log('Nest Ready'))
    .catch(err => console.error('Nest broken', err));


export const api = functions.https.onRequest(server);

Step 6 - Build, Serve, Deploy

npm run build
firebase serve --only functions
firebase deploy --only functions

Option B - Add Nest to the Functions Source

In this setup, we perform a fresh install of Nest in the Functions source code. This is a good approach if you have existing background functions, but want to wrap Nest as an HTTP function.

Step 1 - Initialize Cloud Functions

Initialize Cloud Functions making sure to choose the TypeScript option.

npm i -g firebase-tools
firebase init functions

Step 2 - Install NestJS

Install Nest. If you have an existing project, also copy over the other dependencies from your Package.json.

cd functions
npm i --save @nestjs/core @nestjs/common rxjs reflect-metadata express @nestjs/platform-express

Step 3 - Add NestCLI Support

One of the best features in Nest is the CLI. Let’s add support by creating the following file:

functions/nest-cli.json

{
    "language": "ts",
    "collection": "@nestjs/schematics",
    "sourceRoot": "src"
  }
  

Step 4 - Update the TS Config

Nest uses TypeScript features that are not enabled in Cloud Functions by default. Let’s change that.

functions/tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "noImplicitReturns": true,
    "noUnusedLocals": true,
    "outDir": "lib",
    "sourceMap": true,
    "strict": false,
    "target": "es2017",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "declaration": true,
    "removeComments": true,
    "baseUrl": "./",
    "incremental": true,
    "esModuleInterop": true
  },
  "compileOnSave": true,
  "include": [
    "src"
  ]
}

Step 5 - Generate an App Module

nest generate module app --flat


nest generate controller egg

The file structure of Nest + Cloud Functions

Step 6 - Create the Server

Lastly, create the Nest server and wrap it in a Cloud Function. It’s purpose is to export an ExpressJS app and expose a function that wraps it with Nest.

functions/src/index.ts

import * as functions from 'firebase-functions';
import { NestFactory } from '@nestjs/core';
import { ExpressAdapter } from '@nestjs/platform-express';
import { AppModule } from './app.module';
import express from 'express';


const server = express();


const createNestServer = async (expressInstance) => {
  const app = await NestFactory.create(
    AppModule,
    new ExpressAdapter(expressInstance),
  );


  return app.init();
};




createNestServer(server)
    .then(v => console.log('Nest Ready'))
    .catch(err => console.error('Nest broken', err));


export const api = functions.https.onRequest(server);

Step 7 - Build, Serve, Deploy

cd functions
npm run serve


firebase deploy --only functions

The should give you a URL that looks like [**http://localhost:5000/YOUR-PROJECT/REGION/api/eggs**](http://localhost:5000/YOUR-PROJECT/REGION/api/eggs "**http://localhost:5000/YOUR-PROJECT/REGION/api/eggs**") where you can start testing the API. Happy Nesting 🥚🥚🥚!

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☞ How to Role-Based Access Control in a Node.js application

☞ How to Build Node.js Modules with Rust

☞ Node.js Tutorial for Beginners in 2020

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#node-js #javascript