How to deploy express app on netlify

Step 1: Login to netlify.com from browser (preferably from default browser using github account)

https://www.netlify.com/

Install netlify locally

npm install netlify-cli -g

Login to netlify from console

netlify init

Step 2: Create project locally with api file projectfolder/functions/api.js

const express = require('express');
const serverless = require('serverless-http');
const app = express();
const router = express.Router();

router.get('/', (req, res) => {
  res.send('App is running..');
});

app.use('/.netlify/functions/api', router);
module.exports.handler = serverless(app);

//const port = 8080;
//app.listen(process.env.PORT || port, () => {	
//	console.log(`Listening on port ${port}`);
//});

Step 3: As we are deploying using lambda function create projectfolder/netlify.toml in project root directory

[build]
    functions = "functions"

Step 4: Modify package.json file

{
    "scripts": {
      "build": "netlify deploy --prod"
    },
    "dependencies": {
      "express": "^4.18.2",
      "netlify-cli": "^12.7.2",
      "netlify-lambda": "^2.0.15",
      "serverless-http": "^3.2.0"
    }
}

Step 5: Install required packages/modules

npm i express

Step 6: Test application locally

netlify functions:serve

Step 7: Build the project and deploy on netlify

NOTE: If you are running it for 1st time then chose Create & configure a new site

npm run build

Access api from browser/postman

https://yourproject.netlify.app/.netlify/functions/api

You can check your functions api in netlify portal as well

https://app.netlify.com/sites/<your-project>/functions/api

CRUDL APP

api.js

const conn_str = "mongodb+srv://<username>:<password>@cluster0.<clusterid>.mongodb.net/<databasename>?retryWrites=true&w=majority";
const mongoose = require("mongoose");

mongoose.connect(conn_str)
.then(() => console.log("Connected successfully..."))
.catch( (error) => console.log(error) );


const express = require("express");
const serverless = require('serverless-http');
const app = express();
const router = express.Router();
var cors = require('cors')
app.use(express.json());
app.use(cors())

const empSchema = new mongoose.Schema(    {
    name: String,
    contact_number: String,
    address: String,
    salary: Number,
    employee_id: Number,
    role: String
});

const emp = mongoose.models.emps || new mongoose.model("emps", empSchema);

router.get('/', (req, res) => {
    res.send('App is running..');
});

router.get("/employees", async (req, res) => {
    // var data = [{name: "hari", salary: 25000}, {name: "sameer", salary: 23000}]
    let data = await emp.find();
    res.send(data)
})

//fetch single document by id
//http://localhost:8989/employees/657d397eea713389134d1ffa

router.get("/employees/:id", async (req, res) => {
    // console.log(req.params)
    let data = await emp.find({_id: req.params['id']});
    res.send(data[0])
})

//update document by id
router.put("/employees", async (req, res) => {

	let u_data = await emp.updateOne({"_id": req.body.id}, {
		"$set": {
			"name" : req.body.name,
			"salary" : req.body.salary,
		}
	});
	
	res.send(u_data);

})


//http://localhost:8989/employees?id=657d397eea713389134d1ffe
router.delete("/employees", async (req, res) => {
    let d_data = await emp.deleteOne({"_id": req.query['id']});
	res.send(d_data);
})

router.post("/employees", async (req, res) => {

    // doc = {
    //     "name":"harsha newly added",
    //     "contact_number":"9833910512",
    //     "address":"mumbai",
    //     "salary":20000,
    //     "employee_id":98829,
    //     "role":"operations"
    // }

    doc = req.body;

    let u = await emp(doc);
	let result = u.save();
	res.send(doc);

})

app.use('/.netlify/functions/api', router);
module.exports.handler = serverless(app);