In this article iam gonna explain you how you can create firebase function, deploy and work with firebase function

Step 1: Create a Firebase Project or you can skip this step of you have already created your firebase project

• Go to https://firebase.google.com and click on Get Started

• Proceed to click on Create a project.

• Enter a project name and check yes if you wish to add analytics to your project.

• Wait for the project to be created.

Step 2 Install firebase tools and initialize firebase function

• Run below command to install firebase tools globally

npm install -g firebase-tools

• Initialize firebase function

firebase login

firebase init

• Select Functions option in below step

$ firebase init
> ? Which Firebase features do you want to set up for this directory? Press Space to select features, then Enter to confirm your choices
. (Press <space> to select, <a> to toggle all, <i> to invert selection, and <enter> to proceed)
❯◯ Realtime Database: Configure a security rules file for Realtime Database and (optionally) provision default instance
 ◯ Firestore: Configure security rules and indexes files for Firestore
 ◯ Functions: Configure a Cloud Functions directory and its files
 ◯ Hosting: Configure files for Firebase Hosting and (optionally) set up GitHub Action deploys
 ◯ Hosting: Set up GitHub Action deploys
 ◯ Storage: Configure a security rules file for Cloud Storage
 ◯ Emulators: Set up local emulators for Firebase products
(Move up and down to reveal more choices)

• Select Language

? What language would you like to use to write Cloud Functions? (Use arrow keys)
❯ JavaScript
  TypeScript

• Install packages

? What language would you like to use to write Cloud Functions? JavaScript
? Do you want to use ESLint to catch probable bugs and enforce style? No
✔ Wrote functions/package.json
✔ Wrote functions/index.js
✔ Wrote functions/.gitignore
? Do you want to install dependencies with npm now? (Y/n) Yes

Step 3 Write your function inside functions/index.js file and deploy

Once function initialized and created you will see a folder functions and inside that folder you will have a main file named as index.js where you can define your function

A example function has already been created for you just un comment that

const functions = require("firebase-functions");

// // Create and Deploy Your First Cloud Functions
// // https://firebase.google.com/docs/functions/write-firebase-functions
//
exports.helloWorld = functions.https.onRequest((request, response) => {
  functions.logger.info("Hello logs!", { structuredData: true });
  response.send("Hello from Firebase!");
});

• Deploy your function using below command

firebase deploy --only functions

• Once deployed you can access the function just replace the project id with your firebase project id

https://us-central1-<project-id>.cloudfunctions.net/helloWorld