Gain insights into Express.js essentials—routing, middleware, and RESTful APIs. Learn to integrate MongoDB, JWT authentication, validation, real-time features, and logging for scalable back-end apps.

express.tar.gz

JWT_SECRET

NODE_ENV

Express App

Express code

Express code-module

Express code-silent

Express App-p4000

Express App-test

Express App-database

Express App-database-tmux

Express App-uploads

Express-mysql

Express.js is a popular Node.js framework, especially useful for building APIs and server-side apps. It’s lightweight, unopinionated, and flexible, giving you full control over how your app is structured. Whether new to backend development or ready to build production-grade services using JavaScript, Express is a great place to start.

In this course, you’ll begin with a quick review of Node.js and asynchronous JavaScript. Then, you’ll cover Express.js essentials like routing, middleware, and modular app structure. You’ll learn to build RESTful APIs, connect your app to a database, and implement JSON web tokens (JWT) authentication. You’ll also explore validation and sanitization for added security. Finally, you’ll understand templating engines, real-time features using Socket.IO, and structured logging using Winston.

After completing this course, you’ll have a solid grasp of Express.js and the confidence to build secure, scalable, production-ready backend applications from scratch.

Learn Express.js

In an EJS template, which syntax is used to output the value of a variable?

In an EJS template, which syntax is used to output the value of a variable?

`<% %>` inserts values; `<%= %>` performs logic

`<% %>` is for comments; `<%= %>` is for printing

`<% %>` runs logic without output; `<%= %>` outputs evaluated content

What is the key difference between `<% %>` and `<%= %>` in EJS templates?

What is the key difference between <code>&lt;% %&gt;</code> and <code>&lt;%= %&gt;</code> in EJS templates?

It inserts the contents of another EJS file as unescaped HTML.

It comments out a portion of the template.

What does the following EJS directive do?
```js
<%- include('partials/header') %>
```

What does the following EJS directive do?
<pre><code class="language-js">&lt;%- include('partials/header') %&gt;
</code></pre>

To tell Express where to find the template files

What’s the purpose of setting `app.set('views', './views')` in Express?

What’s the purpose of setting <code>app.set('views', './views')</code> in Express?

It requires closing tags for every element.

It uses indentation instead of closing HTML tags.

Which statement about Pug syntax is *true*?

Which statement about Pug syntax is true?

It allows serving static files more efficiently.

Express doesn't support Socket$\text{}$.io natively.

We need access to the HTTP server instance to attach Socket$\text{}$.io.

It improves performance for all HTTP requests.

What is the main reason for manually creating an HTTP server when using Socket$\text{}$.io with Express?

What is the main reason for manually creating an HTTP server when using Socket<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow></mrow><annotation encoding="application/x-tex">\text{}</annotation></semantics></math>.io with Express?

`socket.emit()` broadcasts to all clients, while `io.emit()` sends to one.

`socket.emit()` sends to the connected client, while `io.emit()` broadcasts to all.

`socket.emit()` is used only on the client side.

What is the difference between `socket.emit()` and `io.emit()` in Socket$\text{}$.io?

What is the difference between <code>socket.emit()</code> and <code>io.emit()</code> in Socket<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow></mrow><annotation encoding="application/x-tex">\text{}</annotation></semantics></math>.io?

To prevent multiple messages from sending at once

To keep the socket connection alive by preventing page reload

It’s required to use Socket$\text{}$.io.

In the client-side code, why is `e.preventDefault()` called inside the form submission handler?

In the client-side code, why is <code>e.preventDefault()</code> called inside the form submission handler?

Which feature is *not* provided by Socket$\text{}$.io out of the box?

Which feature is not provided by Socket<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow></mrow><annotation encoding="application/x-tex">\text{}</annotation></semantics></math>.io out of the box?

Nothing happens unless the server manually pings the client.

The server must manually detect the disconnection.

The socket stays alive until the server is restarted.


The server automatically receives a `disconnect` event.

What happens when a user closes the browser tab in a Socket$\text{}$.io-enabled chat app?

What happens when a user closes the browser tab in a Socket<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow></mrow><annotation encoding="application/x-tex">\text{}</annotation></semantics></math>.io-enabled chat app?

A mechanism that defines where logs are sent or stored

To get colorized logs and encrypted output

To pipe structured HTTP logs into Winston for central logging

Why might a developer combine morgan and Winston in an Express app?

Why might a developer combine morgan and Winston in an Express app?

What log level does Winston use in the following line?

```js
logger.info('User registered', { userId: 'abc123' });
```

What log level does Winston use in the following line?
<pre><code class="language-js">logger.info('User registered', { userId: 'abc123' });
</code></pre>

Rotates logs by time or size to prevent infinite growth

What is the purpose of `winston-daily-rotate-file`?

What is the purpose of <code>winston-daily-rotate-file</code>?

Test your understanding of rendering dynamic views, using Socket.io for real-time features, and logging with Winston.

Course Orientation and Preparations

Getting Started with Express.js

Diving Deeper into Routing

Mastering Middleware

Building RESTful APIs and Integrating Databases

Securing Your Express Applications

Beyond APIs: UI Rendering, Real-Time Communication, and Logging in Express

DevConnector Project

Conclusion

Quiz: Templating, Real-Time Communication, and Logging