Understanding Node.js Event-Driven Architecture and Performance

Today’s focus: The JavaScript Event Loop Most developers use async/await. But fewer understand what actually happens behind the scenes when asynchronous code runs. In a MERN application, every API request, database operation, and real-time update depends on the Event Loop. Here’s the simplified flow: 1️⃣ Call Stack – Executes synchronous code (Code runs line by line ) 2️⃣ Web APIs / Node APIs – Handle async operations (setTimeout, fetch, DB calls) 3️⃣ Callback Queue / Microtask Queue – Stores completed async callbacks 4️⃣ Event Loop – Moves tasks back to the stack when it’s empty Why this matters for MERN developers: • Node.js is single-threaded • Blocking code can freeze the entire server • Efficient async handling improves scalability Understanding the Event Loop helps you: ✔ Write non-blocking backend logic ✔ Design scalable APIs ✔ Avoid performance bottlenecks ✔ Debug async issues confidently In Web development, writing code is one thing. Understanding how it executes is another. Today I deepened my understanding of the Event Loop to improve how I design backend systems. #MERN #JavaScript #EventLoop #NodeJS #FullStack #BackendDevelopment #LearningInPublic #SheryiansCodingSchool Ankur Prajapati , Sheryians Coding School

🚀 Day 6/21 | 21-Day MERN Stack Challenge Today’s focus was understanding React architecture and scalable frontend design using our ongoing full-stack project as a practical example. 🧩 What I worked on • Organized the project using a proper folder structure to separate components, pages, services, and utilities • Designed a frontend architecture following a layered approach: UI → Hooks → State Layer → API Layer • Built a clear component hierarchy and understood how data flows across the application ⚙️ Structured & Maintainable Code ✅ Separated UI logic, API calls, and state management for better readability and maintainability ✅ Applied scalable design thinking to keep the project clean as it grows 🧠 Key Learning Learned how large React applications are structured in real-world projects to support scalability, easier debugging, and long-term maintainability. Moving beyond just writing components — now focusing on building applications with proper architecture 🚀 Sheryians Coding School Harsh Vandana Sharma Ankur Prajapati Satwik Raj #21DayChallenge #MERNStack #ReactJS #FrontendArchitecture #WebDevelopment #ScalableDesign #FrontendDevelopment #JavaScript #LearningInPublic #FullStackDeveloper

One Powerful Feature of NestJS: Dependency Injection Dependency Injection is a core concept in NestJS that helps developers write clean and reusable code. Instead of creating objects manually, NestJS automatically injects dependencies where they are needed. Example: @Injectable() export class UsersService { getUsers() { return ["Yasir", "Ahmed", "Sara"]; } } Controller using the service: @Controller('users') export class UsersController { constructor(private usersService: UsersService) {} @Get() getAllUsers() { return this.usersService.getUsers(); } } ✅ Benefits: ✔ Better code organization ✔ Easy testing ✔ Loose coupling between components Learning these concepts helps build scalable backend systems. #NestJS #DependencyInjection #NodeJS #BackendDevelopment #CleanCode

Day 5/21: Entering the World of Backend & Node.js 🌐 Today marks Day 5 of my 21-day learning challenge, and it’s a big one—I’ve officially started my journey into Backend Development. The Shift to Server-Side: After focusing on the browser, today was about understanding how JavaScript lives outside of it. I dived deep into the core foundations of Node.js and the Express.js ecosystem. Key Backend Takeaways: Runtime Environments: Exploring how Node.js allows us to execute JavaScript directly on a server/machine. Package Management: Mastering npm for project initialization and dependency management. Server Architecture: Understanding the request-response cycle and building my first basic server with Express. Environment Efficiency: Setting up nodemon to streamline the development workflow. A Quick Refresh (Frontend): To keep my DOM manipulation skills sharp while diving into logic, I also built a smooth Mouse Follower using HTML, SCSS, and Vanilla JavaScript. It was a great way to "freshen up" on event listeners and CSS transitions before fully immersing myself in server-side code. One big realization today: The Backend isn't just about code; it's about communication. Learning how a server listens and responds is the first step toward building truly full-stack applications. Check out the screen recording below to see the mouse follower in action! 🖱️✨ Sheryians Coding School Mentor: Ankur Prajapati #SheryiansCodingSchool #Cohort2_0 #21DaysChallenge #NodeJS #ExpressJS #BackendDevelopment #WebDevelopment #Javascript #FullStackJourney

Over the past few days, I’ve been going deeper into backend fundamentals using Express and Node.js - not just writing APIs, but understanding what’s happening under the hood. Here’s what I worked on: • Built REST APIs (GET, POST, PUT, DELETE) • Explored how express.json() parses request bodies • Practiced handling CORS and understood why browsers block cross-origin requests • Compared fetch vs axios - especially around headers, JSON parsing, and error handling • Learned how middleware and next() actually control request flow One small but powerful realization: It’s easy to make something “work”. It’s much harder - and more valuable - to understand why it works. For example: Why does the server fail without Content-Type: application/json? Why doesn’t fetch throw errors on 400/500 responses? What exactly happens when middleware doesn’t call next()? These details are what separate surface-level coding from real backend engineering. My focus right now is simple: Build strong fundamentals in MERN within 30 days - with depth, not shortcuts. If you’re also building in public or working on backend systems, I’d love to connect and exchange learnings. #MERN #BackendDevelopment #NodeJS #ExpressJS #JavaScript #LearningInPublic

I Started Learning Node.js to Strengthen My Backend Skills Instead of jumping straight into frameworks, I focused on understanding how Node.js actually works. Here’s what I’ve covered so far: Core Foundations • How Node.js executes JavaScript outside the browser • Why there is no window or document object on the server • The difference between browser runtime and server runtime • Event-driven, non-blocking architecture fundamentals Modules & Code Organization • CommonJS module system • module.exports and require() • Named exports vs aggregated exports • Structuring code across multiple files Understanding this properly makes scaling projects easier later. Core Built-in Modules • fs → Reading and writing files • path → Handling cross-platform file paths • os → Accessing system-level information Instead of just using frameworks blindly, I wanted clarity on how backend logic interacts with the operating system. Why This Matters Many developers jump directly into Express or NestJS without understanding: How Node handles I/O How modules are resolved How the event loop behaves How blocking operations affect performance I’m focusing on fundamentals first. Because frameworks change. Core runtime understanding does not. Now here’s the uncomfortable question you should ask yourself next: Have you studied: The event loop phases? Microtasks vs macrotasks? Streams? Buffers? Async vs sync FS trade-offs? How Node handles concurrency internally? If not, you’re still at beginner level — and that’s fine. Just don’t confuse starting with mastering. #NodeJS #BackendDevelopment #JavaScript #FullStackDeveloper #SoftwareEngineering #LearningInPublic #Developers

I started reading NodeBook The Deep Runtime Knowledge and it honestly changed how I look at Node.js. We use Node.js every day. We write async/await. We trust the event loop. We debug “weird” performance issues. But how many of us actually understand what’s happening under the hood? 👀 This deep dive is pushing me to really understand: How the event loop actually works What “non-blocking” truly means in practice How memory, call stack, and async tasks interact Why performance bugs appear even in “simple” code Big reminder for me: Frameworks make us productive. Runtime knowledge makes us dangerous (in a good way 😄). If you’re serious about building scalable, reliable Node.js systems, learning the internals isn’t optional anymore. Time to go deeper. Let’s build better. 🚀 #NodeJS #JavaScript #BackendEngineering #SoftwareEngineering #WebDevelopment #Performance #Scalability #LearningInPublic #BuildInPublic #DeveloperLife #TechGrowth #Programming

🚀 Started Learning NestJS – Taking My Backend Skills to the Next Level 🚀 As someone with experience in Node.js & Express, I’ve recently started learning NestJS, and the difference in architecture is impressive. NestJS brings structure and scalability to Node.js applications — especially useful for building enterprise-level and microservices-based systems. Here are a few powerful concepts I’ve been exploring: 🔹 Guards – Handle authentication & authorization logic before request reaches the route handler. 🔹 Pipes – Used for validation and transformation of request data. 🔹 DTOs (Data Transfer Objects) – Help define strict data contracts between client and server. 🔹 Filters – Centralized exception handling for cleaner error management. 🔹 Interceptors – Transform responses, logging, performance tracking, etc. 🔹 Modules & Dependency Injection – Clean, scalable architecture out of the box. 💡 Compared to Express (which is minimal and flexible), NestJS provides a more opinionated, structured approach — similar to Spring Boot in the Java ecosystem. As someone aiming to build scalable backend systems and microservices, this feels like the right direction. Excited to go deeper into: • Microservices architecture • WebSockets with NestJS • Authentication & RBAC • Clean Architecture patterns #NodeJS #NestJS #BackendDevelopment #Microservices #SoftwareEngineering #LearningJourney

While building projects, I discovered an interesting insight: most tutorials emphasize features, but real engineering revolves around designing how the system operates behind the scenes. One of the projects I developed is SkillSwap, a platform where individuals can exchange skills with one another. For example, someone proficient in UI Design can connect with someone knowledgeable in Python, allowing both to learn from each other. In building SkillSwap, I concentrated on creating a simple yet clear architecture: - Frontend – React: Handles the user interface, authentication flow, and interactions such as posting skills and sending exchange requests. - Backend – Node.js + Express: Responsible for core logic, including: - Managing user accounts - Handling skill listings - Processing skill exchange requests - Managing API communication between the frontend and database - Database – MongoDB: Stores user profiles, skills offered, and skills users wish to learn. The basic flow of the system is as follows: User → React UI → Express API → MongoDB → API Response → UI Update This project taught me that building software isn’t solely about writing code. Understanding how data flows through the system simplifies the design, building, and debugging processes. I look forward to working on more backend-focused systems and exploring improved methods for designing scalable applications. #BackendDevelopment #NodeJS #MERNStack #SoftwareEngineering #Projects #LearningByBuilding

🚀 Day-11 of Understanding MERN Stack In-Depth 🎯 Topic: Streams in Node.js (Readable, Writable, Duplex, Transform) Today, I explored one of the most powerful and efficient concepts in Node.js — Streams. This concept completely changed how I think about handling large data in backend systems. 📌 What are Streams in Node.js? • Streams are used to handle large amounts of data piece-by-piece (chunks) instead of loading everything into memory at once. • This makes Node.js very memory efficient and fast. • Instead of waiting for the full data, Node.js processes data as it arrives. Example: Reading a 1GB file without loading the entire file into RAM. 📌 Types of Streams in Node.js: 1️⃣ Readable Streams • Used to read data (example: fs.createReadStream()) • Example use: Reading files, receiving data from client 2️⃣ Writable Streams • Used to write data (example: fs.createWriteStream()) • Example use: Writing files, sending response to client 3️⃣ Duplex Streams • Both readable and writable • Example use: Network sockets 4️⃣ Transform Streams • Modify data while reading and writing • Example use: File compression (zlib), encryption 📌 Why Streams are Used in Real Applications? • Handling large files (video upload, download) • Streaming data in real-time applications • File compression • Data processing pipelines • Improving performance and reducing memory usage Example: YouTube, Netflix use streaming concept. 📌 What I Learned Today: • How Node.js handles large data efficiently • Why streams are better than traditional file reading • How streaming improves backend performance • Real world use of streams in file upload and APIs • Why Node.js is called non-blocking and efficient 💡 Key Takeaway: Streams make Node.js extremely powerful for building scalable and high-performance backend systems. Excited to explore more deep backend concepts tomorrow. 🔥 #Day11 #MERN #NodeJS #BackendDevelopment #FullStackDeveloper #JavaScript #LearningInPublic