Express JS provides various HTTP methods to interact with data. Among these methods, the PUT method is commonly used to update existing resources.

Prerequisites

• Node JS
• Express JS

In this article, we are going to setup the request endpoint on the server side using Express JS and Node JS. This endpoint will be responsible for updating the existing data in your database.

Steps to create a project and install the required modules

Step 1: Make a root directory using the following command.

mkdir root

Step 2: Initialize NPM via the following command.

npm init -y

Step 3: Install Express in your project via the given command of NPM.

npm i express

Dependencies:

"dependencies": {
      "express": "^4.18.2",
}

Project Structure

Approach

In this approach, we setup two endpoints for server-side code: one is get() and another is put(). get() will be used to display hard-coded data present in the backend, “hello world,” and put() will be used to update the database, but here we are not connecting databases; we received data in the backend and displayed that data in the console. When the user wants to save that data, they can easily save it using the dot operator.

Example: Implementation of above approach.

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

app.use(express.json())

let data = "Hello Word!";
app.get("/", (req, res) => {
    console.log(data);
    res.send(data);
})

app.put("/", (req, res) => {
    console.log(req.body);
    res.send("Data Recieved Successfully!");
})

app.listen(3000, () => { console.log("Server Connected!") });

Output:

Conclusion

The HTTP PUT method in Express.js allows you to update the existing resources within the application. Using this, you can modify specific data based on unique identifiers. This is very important part of building RESTful APIs and enables applications to perform CRUD (Create, Read, Update, Delete) operations.