How to test DELETE Method of Express with Postman ?

The DELETE method in web development plays a crucial role in handling resource deletions on the server. As one of the HTTP methods, its primary purpose is to request the removal of a resource identified by a specific URI. In this article, we will see how we can use the Delete method in different scenarios efficiently.

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 leverage 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.

Javascript

// 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.

Javascript

// 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)

Javascript

// 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: