Express.js | app.put() Function

The app.put() function routes the HTTP PUT requests to the specified path with the specified callback functions. 

Syntax:

app.put(path, callback [, callback ...])

Arguments:

• Path: The path for which the middleware function is invoked and can be any of the:
  • A string represents a path.
  • A path pattern.
  • A regular expression pattern to match paths.
  • An array of combinations of any of the above.
• Callback: Callback functions can be:
  • A middleware function.
  • A series of middleware functions (separated by commas).
  • An array of middleware functions.
  • A combination of all of the above.

Installation of the express module:

You can visit the link to Install the express module. You can install this package by using this command.

npm install express

After installing the express module, you can check your express version in the command prompt using the command.

npm version express

After that, you can just create a folder and add a file, for example, index.js. To run this file you need to run the following command.

node index.js

Project Structure:

Filename: index.js

javascript

const express = require('express');
const app = express();
const PORT = 3000;

app.put('/', (req, res) => {
    res.send("PUT Request Called")
})

app.listen(PORT, function (err) {
    if (err) console.log(err);
    console.log("Server listening on PORT", PORT);
});

Steps to run the program:

Make sure you have installed the express module using the following command:

npm install express

Run the index.js file using the below command:

node index.js

Output:

Console Output:

Server listening on PORT 3000

Browser Output:

Now make a PUT request to http://localhost:3000/ and you will get the following output:

PUT Request Called

So this is how you can use the express app.put() function which routes HTTP PUT requests to the specified path with the specified callback functions.