The Lagos Traffic Problem (aka Your Codebase).
You're stuck in Lagos traffic at 6 PM on a Friday. Every car is doing whatever it wants, weaving through, danfos stopping anywhere, private cars changing lanes without indicators. I bet that's your current React app 😀 . Everything is connected to everything. Your components are fetching data, updating state, handling business logic, and rendering UI all in one 500-line file called Dashboard.tsx.
Let’s be honest, most React codebases start as “side projects that got too serious.” 😅
One day you’re building a quick login screen, before you know it, you’re managing a full fintech product with 40+ screens, complex states, network calls, caching, and some poor soul screaming “Who added this useEffect that runs 12 times on mount?!”
As a senior engineer (or “oga dev” as we say), you know the vibes: we crave structure, scalability, and clarity, but we also want speed, flexibility, and type safety.
So today, let’s talk about how to architect your React frontend like a proper enterprise system, applying Domain-Driven Design (DDD), Clean Architecture, and CQRS, all in TypeScript, of course (because we like our bugs caught early 👀).
The "It Works" Trap
Let me tell you about my friend Deewills (not his real name, but if you're reading this Deewills, you know yourself). Deewills built a beautiful fintech dashboard. Users could check balances, transfer money, pay bills, everything worked perfectly, for three months.
Then the business wanted to add savings features. Simple enough, right? Wrong.
Deewills opened
TransactionComponent.tsx
and found 800 lines of code. The component was fetching user data, calculating balances, handling transfers, managing form state, talking to three different APIs, and somehow also controlling the notification system. It was like opening a danfo and finding it's also a mechanic shop, a provision store, and somehow running a small farm in the back. The "small feature" took three weeks. The bugs took another two.
Deewills now works as a photographer (he's doing fine, but that's not the point).
Domain-Driven Design
(DDD) is like organizing Lagos. Imagine if we actually had proper zones: Ikeja for business, VI for finance, Yaba for tech. Each area handles its own thing, has its own rules, and talks to other areas through proper channels (not megaphone at night).
In your React app, this means:
1. Domain Layer (The Core Business)
This is where your actual business logic lives. Think of it like the CBN, it sets the rules for how money works in your app, and it doesn't care whether you're using React, Vue, or building a mobile app with Flutter.
2. Application Layer (The Traffic Controllers)
This is where CQRS comes in. CQRS stands for Command Query Responsibility Segregation, which in normal person language means: "Separate your reading from your writing, don't mix them like jollof and ofada rice."
Commands = Things that change state (Mutations, the troublemakers)
Queries = Things that just read data (Safe, reliable, your mother's favorite)
3. Infrastructure Layer (The Actual Implementation)
This is where you deal with the dirty work: APIs, databases, localStorage, that one legacy SOAP service the bank refuses to update.
Common Objections (And Why They're Wrong)
This is too much boilerplate!
Omo, you know wetin be boilerplate? Debugging for 3 days because business logic is scattered everywhere. That's boilerplate. This is structure.
We're a startup, we need to move fast!
You know what's not fast? Rewriting your entire app in 6 months because the codebase became unmaintainable. Ask Deewills.
My team won't understand this!
Your team understands Lagos traffic, they can understand layers. Organize your code like we organize our markets: separate sections for separate things.
We're too small for this!
You're never too small for clean code. Even a one-man project benefits from not having to remember where you put which logic.The Bottom Line
Stop fighting your codebase. Stop spending days making "small changes." Stop having every feature break something unrelated.
DDD + CQRS + Clean Architecture isn't about being fancy. It's about writing code that:
- You can understand 6 months later
- Your colleague can modify without a PhD
- Actually scales when your startup blows up
- Doesn't make you want to resign when the PM says "one small feature"
Your future self will thank you. Your team will thank you. Your 2 AM debugging sessions will become rare. And when someone asks "Why is this codebase so clean?" you can smile and say "Because we stopped building spaghetti."
Now go forth and refactor. Your App.tsx with 2000 lines is waiting.
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