DELETE route handling in Express - Mini Project: Build & Apply

DELETE Route Handling in Express

📖 Scenario: You are building a simple Express server to manage a list of books. Users can add, view, and delete books. Now, you will add the ability to delete a book by its ID using a DELETE route.

🎯 Goal: Create an Express DELETE route that removes a book from the list by its id.

📋 What You'll Learn

Create an array called books with three book objects, each having id and title properties.

Create a variable called bookIdToDelete and set it to 2.

Use the filter method on books to remove the book with id equal to bookIdToDelete.

Add an Express DELETE route at /books/:id that deletes the book with the given id from books.

💡 Why This Matters

🌍 Real World

Deleting items from a list via an API is common in web apps, such as removing products from a shopping cart or deleting user posts.

💼 Career

Understanding how to handle DELETE routes in Express is essential for backend web development roles that build RESTful APIs.

1

Create the initial books array

Create an array called books with these exact objects: { id: 1, title: 'Book One' }, { id: 2, title: 'Book Two' }, and { id: 3, title: 'Book Three' }.

Express

# Your code here

Need a hint?

Use const books = [ ... ] with three objects inside.

2

Set the book ID to delete

Create a variable called bookIdToDelete and set it to the number 2.

Express

const books = [
  { id: 1, title: 'Book One' },
  { id: 2, title: 'Book Two' },
  { id: 3, title: 'Book Three' }
];

# Your code here

Need a hint?

Use const bookIdToDelete = 2; to store the ID.

3

Filter out the book to delete

Use the filter method on books to create a new array without the book whose id matches bookIdToDelete. Assign this new array back to books.

Express

const books = [
  { id: 1, title: 'Book One' },
  { id: 2, title: 'Book Two' },
  { id: 3, title: 'Book Three' }
];

const bookIdToDelete = 2;

# Your code here

Need a hint?

Use books = books.filter(book => book.id !== bookIdToDelete); to remove the book.

4

Add the Express DELETE route

Add an Express DELETE route at /books/:id. Inside the route handler, convert req.params.id to a number, then update books by filtering out the book with that id. Send a JSON response with { message: 'Book deleted' }.

Express

let books = [
  { id: 1, title: 'Book One' },
  { id: 2, title: 'Book Two' },
  { id: 3, title: 'Book Three' }
];

const bookIdToDelete = 2;

books = books.filter(book => book.id !== bookIdToDelete);

// Your code here

Need a hint?

Use app.delete('/books/:id', (req, res) => { ... }) and inside convert req.params.id to a number, then filter books, then send JSON response.