expressjsHow do I use Express.js to get a user's IP address?

Using Express.js to get a user's IP address is very simple. The following example will show how to do this:

const express = require('express')
const app = express()

app.get('/', (req, res) => {
    const ip = req.ip
    console.log(ip)
    res.send(ip)
})

app.listen(3000, () => console.log('Listening on port 3000'))

In the example above, the req object is used to get the user's IP address. The req.ip property returns the user's IP address as a string. The IP address is then printed out to the console and sent as a response to the user.

Code explanation

• const express = require('express'): imports the Express.js module.
• const app = express(): creates an instance of the Express.js application.
• app.get('/', (req, res) => { ... }): defines a route handler for the GET request to the / route.
• const ip = req.ip: gets the user's IP address from the req object.
• console.log(ip): prints the IP address to the console.
• res.send(ip): sends the IP address as a response to the user.
• app.listen(3000, () => console.log('Listening on port 3000')): starts the Express.js server on port 3000.

The output of the example code will be the user's IP address printed out to the console.

Helpful links

• Express.js Documentation
• Express.js Request Object Documentation

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