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:${port}`))
//visit localhost:3000
// assuming you have done 1) npm init 2) npm install express
Example 2: node.js express
const express = require('express')
const app = express()
const port = 3000
app.get('/', (req, res) => res.send('Hello World!'))
app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))
Example 3: node js express
basic server
const express =require('express');
const app = express();
const PORT = 5000;
app.get('/',(req,res)=>{
res.json({message: 'Welcome to the backend'})
})
app.listen(PORT ,()=>console.log(`Connected to ${PORT}`)
Example 4: express js
const express = require('express')
const app = express()
const port = 3000
app.get('/', (req, res) => {
res.send('Hello World!')
})
app.listen(port, () => {
console.log(`Example app listening at http://localhost:${port}`)
})
Example 5: 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:
$env:DEBUG='myapp:*'; npm start
Example 6: node js express
// node js -> express -> basic example: static folder, 404 page
const express = require('express');
const path = require('path');
const PORT = process.env.PORT || 5000;
const app = express();
function error404(req, res) {
res.status(404);
if (req.accepts('html')) {
res.sendFile(path.join(__dirname, 'public/errors/404.html'));
return;
}
if (req.accepts('json')) {
res.send({
status: 404,
error: 'Not found'
});
return;
}
res.type('txt').send('404 - Not found');
}
app
.use(express.static(path.join(__dirname, 'public')))
.use(error404)
.listen(PORT, () => console.log(`Listening on ${ PORT }`));