express js

1$ npm install express --no-save
2

1
2const express = require('express')
3const app = express()
4const port = 3000
5
6app.get('/', (req, res) => {
7  res.send('Hello World!')
8})
9
10app.listen(port, () => {
11  console.log(`Example app listening at http://localhost:${port}`)
12})
13
14

1const express = require('express');
2const app = express();
3const port = 3000;
4
5app.get('/', (req, res) => {
6  res.send('Hello World!')
7});
8
9app.listen(port, () => {
10  console.log(`App listening at http://localhost:${port}`)
11});

1Connect With mongodb, cors , dotenv, express
2
3const express = require('express');
4const cors = require('cors')//cors for own server connected with own
5const app = express();
6require("dotenv").config();//dotenv config
7const port = process.env.PORT || 5000;
8
9//Middleware
10app.use(cors());
11app.use(express.json());
12
13const { MongoClient } = require('mongodb');
14const uri = `mongodb+srv://${process.env.DB_USER}:${process.env.DB_PASS}@cluster0.vdirb.mongodb.net/myFirstDatabase?retryWrites=true&w=majority`;
15const client = new MongoClient(uri, { useNewUrlParser: true, useUnifiedTopology: true });
16
17async function run() {
18    try {
19      await client.connect();
20      const database = client.db("insertDB");
21      const servicesCollection = database.collection("volunteers");
22      
23      
24    }
25     finally {
26    //   await client.close();
27    }
28  }
29  run().catch(console.dir);
30
31
32
33app.get('/',(req,res) =>{
34    res.send('Server is ok')
35});
36
37app.listen(port, () =>{
38    console.log('Port is Ok');
39})

1Express is a minimal and flexible Node.js web application framework
2that provides a robust set of features for web and mobile
3applications.

1Express.js, or simply Express, is a web application framework for Node.js,
2released as free and open-source software under the MIT License.
3
4It is designed for building web applications and APIs.
5It has been called the de facto standard server framework for Node.js.