How to test DELETE Method of Express with Postman ?

The DELETE method is an essential part of RESTful web services used to remove specific resources from a server. Whether you are building a simple API or a complex web application, knowing how to use this method effectively is key.

Here, we will explore how to Implement the DELETE method in Express.js using two different approaches direct routing and Express Router. By the end, you will be able to test and verify DELETE operations using postman with ease.

Prerequisites:

• Express.js Framework
• HTTP Methods (DELETE)
• Node.js and npm

We will use the following approaches to test delete method:

Approach 1: Direct Usage in Express JS

In this approach, we use Express JS to handle nested routes and implement the DELETE method, providing a clear and straightforward organization of code.

Syntax:

app.delete('base URL', (req, res) => {
    // DELETE method logic for the base URL
})

app.delete('base URL/Nested URL', (req, res) => {
    // DELETE method logic for the nested URL
})

Example: Write the following code in server.js file.

// Server.js

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

app.delete("/resource", (req, res) => {
    console.log("DELETE Request Successful!");
    res.send("Resource Deleted Successfully");
});

app.delete("/resource/:id", (req, res) => {
    const resourceId = req.params.id;
    console.log(`Deleting resource with ID: ${resourceId}`);
    res.send(`Resource with ID ${resourceId} Deleted Successfully`);
});

app.listen(PORT, () => {
    console.log(`Server established at ${PORT}`);
});

Approach 2: Usage with Express JS Router

This approach involves creating a base URL using Express JS Router, allowing for a cleaner structure and improved code organization.

Syntax:

const router = express.Router();

router.delete('/', (req, res) => {
    // DELETE method logic for the base URL
})

router.delete('/nested', (req, res) => {
    // DELETE method logic for the nested URL
})

Example: Write the following code in server.js file.

// Server.js

const express = require('express');
const app = express();
const PORT = 3000;
const router = express.Router();

router.delete('/', (req, res) => {
    res.send("Deleting Resource");
});

router.delete('/api', (req, res) => {
    res.send("Deleting from /api endpoint");
});

app.use('/resource', router);

app.listen(PORT, () => {
    console.log(`Server established at ${PORT}`);
});

Implementation

In this example, we'll create a basic API for managing a list of books.

Step 1: Initialize a Express Js project and install the required dependencies.

mkdir express-delete-example
cd express-delete-example
npm init -y
npm install express

Project Structure:

The updated dependencies in package.json file will look like:

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

Step 2: Create the main server file (e.g., server.js)

// server.js

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

app.use(express.json());

// Sample data (replace this with a database in a real-world scenario)
let books = [
    { id: 1, title: 'Introduction to Express', author: 'John Doe' },
    { id: 2, title: 'Node.js Basics', author: 'Jane Smith' },
];

// GET method to retrieve all books
app.get('/books', (req, res) => {
    res.json(books);
});

// POST method to add a new book
app.post('/books', (req, res) => {
    const newBook = req.body;
    books.push(newBook);
    res.status(201).json(newBook);
});

// DELETE method to remove a book by ID
app.delete('/books/:id', (req, res) => {
    const bookId = parseInt(req.params.id);
    const index = books.findIndex(book => book.id === bookId);

    if (index !== -1) {
        const deletedBook = books.splice(index, 1)[0];
        res.json({ message: 'Book deleted successfully', deletedBook });
    } else {
        res.status(404).json({ message: 'Book not found' });
    }
});

app.listen(PORT, () => {
    console.log(`Server is running on http://localhost:${PORT}`);
});

To start the server run the following command.

node server.js

Step 3: You can test the DELETE method using Postman, for testing using postman:

• login to your postman account.
• Create New request and paste the url i.e http://localhost:3000/books/1 in request.
• Choose Delete from the methods section.
• click on SEND.
• Now, you can see the Output in the Postman.

Output: