React Anti-Patterns: Fixing Common Mistakes for Clean Code

Hey React devs! If you’ve ever looked back at your own code and thought, “Wait, why did I do it like that?”—you’re not alone. Over-engineering and anti-patterns sneak up on all of us, whether building your first app or wrangling a giant codebase. 

Today, let’s explore mistakes nearly every React developer makes (yes, including me), and how you can sidestep them for faster, cleaner projects.

Why Do Anti-Patterns Happen (and Why Care)?

React gives us loads of freedom, but that leaves room for confusion and blunders. Anti-patterns are habits or shortcuts that feel like a good idea but end up causing bugs, slow performance, or code that’s impossible to maintain. 

By spotting these early, you’ll avoid headaches for yourself and anyone else who works on your code!

Pitfall #1: Overusing State & Causing Unwanted Re-renders

Imagine putting every single piece of data into state—your app will re-render any time, even the tiniest value changes. This drains performance and clutters your logic.

What NOT to do:

How to fix:

Directly derive values inside render:

Pitfall #2: Mutating State Directly

If you change objects or arrays inside state without using the updater, React may ignore your changes or break the UI.

Here’s a classic bug:

How to fix:

Always create a new array/object:

Pitfall #3: Dependency Hell with useEffect

It’s easy to end up with infinite loops or missed updates if useEffect dependencies aren’t handled with care.

Best approach: Only include true dependencies, or leave it empty when you want a one-time effect:

And always clean up after yourself:

Pitfall #4: Context and Global State Overuse

Context is powerful—but don’t pour your entire app’s state into it. Large context objects cause unnecessary renders and tangled logic.

Instead:

• Use Context sparingly for truly global stuff (theme, user, locale)
• Keep UI state (like “modal open”) local to components or use reducers for structured updates

Pitfall #5: Memory Leaks From Unfinished Cleanups

If you have subscriptions, timers, or event listeners, always clean them up in useEffect’s return function. This avoids stray processes chewing up browser memory.

Pitfall #6: Over-Engineering & Abstracting Too Early

Dreaming up the “perfect generic” component before you need it can lead to super complicated code nobody can read.

Example:

Trying to make an ultra-flexible Input that supports every possible type/prop combination. Instead, start with what your project needs, and only abstract when you see repeated patterns.

Bonus: Simple Mistakes to Dodge

• Not using keys in lists:


• Forgetting className (using class by accident)
• Using anonymous functions in JSX, which creates a new function each render:

Summary: Write React Apps You’re Proud Of!

Anti-patterns aren’t a sign you’re a bad developer—they’re growing pains for every React coder. By recognising them, you’ll build cleaner, smoother, and more maintainable apps. Keep code simple. Derive the state when needed. Clean up side effects. Don’t over-engineer. And above all, embrace refactoring as your skill grows.