Example 1: express hello world
//to run : node filename.js
const express = require('express')
const app = express()
const port = 3000
app.get('/', (req, res) => res.send('Hello World!'))
app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))
//visit localhost:3000
// assuming you have done 1) npm init 2) npm install express
Example 2: how to create server in node js using express
You can run the application generator with the npx command (available in Node.js 8.2.0).
$ npx express-generator
For earlier Node versions, install the application generator as a global npm package and then launch it:
$ npm install -g express-generator
For example, the following creates an Express app named myapp. The app will be created in a folder named myapp in the current working directory and the view engine will be set to Pug:
$ express --view=pug myapp
create : myapp
create : myapp/package.json
create : myapp/app.js
create : myapp/public
create : myapp/public/javascripts
create : myapp/public/images
create : myapp/routes
create : myapp/routes/index.js
create : myapp/routes/users.js
create : myapp/public/stylesheets
create : myapp/public/stylesheets/style.css
create : myapp/views
create : myapp/views/index.pug
create : myapp/views/layout.pug
create : myapp/views/error.pug
create : myapp/bin
create : myapp/bin/www
Then install dependencies:
$ cd myapp
$ npm install
On MacOS or Linux, run the app with this command:
$ DEBUG=myapp:* npm start
On Windows Command Prompt, use this command:
> set DEBUG=myapp:* & npm start
On Windows PowerShell, use this command:
PS> $env:DEBUG='myapp:*'; npm start
Then load http://localhost:3000/ in your browser to access the app.
The generated app has the following directory structure:
.
├── app.js
├── bin
│ └── www
├── package.json
├── public
│ ├── images
│ ├── javascripts
│ └── stylesheets
│ └── style.css
├── routes
│ ├── index.js
│ └── users.js
└── views
├── error.pug
├── index.pug
└── layout.pug
7 directories, 9 files
The app structure created by the generator is just one of many ways to structure Express apps. Feel free to use this structure or modify it to best suit your needs.
Example 3: how to make an express server
// this is your code
// ZDev1#4511 on discord if you want more help!
// first you should install express in the terminal
// `npm i express`.
const express = require('express');
const app = express();
// route
app.get('/', (req,res)=>{
// Sending This is the home page! in the page
res.send('This is the home page!');
});
// Listening to the port
let PORT = 3000;
app.listen(PORT)
// FINISH!
Example 4: simple express server
const express = require('express');
const app = express();
const PORT = process.env.PORT || 3000;
app.get('/', (req, res) => {
res.send('<h1>Some HTML</h1>');
res.send('<p>Even more HTML</p>');
});
app.listen(PORT, () => console.log(`Server is listening on port ${PORT}`));
Example 5: create server with express js
// npm init
// npm i express
const express = require('express');
const server = express();
const PORT = 3000;
// Body parser
server.use(express.json());
// Homme page
server.get('/', (req, res) => {
return res.send("<h1 style='text-align: center;'>Hello,<br />from the Express.js server!</h1>");
})
// About page
server.get('/about', (req, res) => {
return res.send('<h2 style="text-align:center">About us</h2>');
})
// 404 page
server.use((req, res, next) =>{
res.status(404);
// respond with html page
if (req.accepts('html')) {
res.sendFile(__dirname + '/error404.html');
return;
}
// respond with json
else if (req.accepts('json')){
res.send({
status: 404,
error: 'Not found'
});
return;
}
// respond with text
else {
res.type('txt').send('Error 404 - Not found');
}
});
// Listening to the port
server.listen(PORT, () => {
console.log(`Server is running on port ${PORT}`);
});
Example 6: sample express app
const express = require('express')
const app = express()
const port = 3000
app.get('/', (req, res) => res.send('Hello World!'))
app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))