### Install Express.js

Source: https://expressjs.com/

Install the Express.js framework using npm. This command adds Express as a dependency to your project.

```bash
npm install express --save
```

--------------------------------

### Basic Express.js 'Hello World' App

Source: https://expressjs.com/

A minimal Express.js application that listens for requests on a specified port and responds with 'Hello World!'. Requires the 'express' module.

```javascript
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 on port ${port}`)
})
```

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