Deleting documents in Express - Mini Project: Build & Apply

Deleting Documents with Express

📖 Scenario: You are building a simple web server using Express. This server manages a list of documents stored in memory. You want to add the ability to delete a document by its ID.

🎯 Goal: Build an Express server that stores documents in an array and allows deleting a document by its id using a DELETE request.

📋 What You'll Learn

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

Create a variable called deleteId and set it to 2.

Use the filter method on documents to remove the document with id equal to deleteId.

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

💡 Why This Matters

🌍 Real World

Deleting documents or records is a common feature in web applications like content management systems, note-taking apps, or admin dashboards.

💼 Career

Understanding how to handle DELETE requests and manipulate data collections is essential for backend developers working with REST APIs.

1

Create the initial documents array

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

Express

// Create the documents array with 3 objects
// Your code here

Need a hint?

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

2

Set the ID to delete

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

Express

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

// Create deleteId variable
// Your code here

Need a hint?

Use const deleteId = 2; to store the ID to delete.

3

Filter out the document to delete

Use the filter method on documents to create a new array without the document whose id equals deleteId. Assign this new array back to documents.

Express

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

const deleteId = 2;

// Filter documents to remove the one with id equal to deleteId
// Your code here

Need a hint?

Use documents = documents.filter(doc => doc.id !== deleteId); to remove the document.

4

Add Express DELETE route to delete documents

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

Express

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

const deleteId = 2;

documents = documents.filter(doc => doc.id !== deleteId);

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

// Add DELETE route at /documents/:id
// Your code here

Need a hint?

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