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Introduction

Custom React hooks are powerful tools that let you abstract, reuse, and organize logic across your components. But with great power comes great responsibility. Poorly written hooks can lead to tangled dependencies, performance issues, or confusing APIs. This guide covers the best practices for writing custom hooks—how to name, structure, organize, optimize, and know when not to use them.

Why Create a Custom Hook?

Before you write one, ask yourself:

✔ Is this logic repeated in multiple components?

✔ Is this logic tied to React lifecycle or hooks (useEffect, useState, etc.)?

✔ Would separating this logic improve readability or testability?

If yes to at least one of the above, a custom hook might be a good idea.

File Structure & Naming Conventions

✅ Naming Your Hook

  • Prefix every custom hook with use (e.g., useForm, useAuth, useWindowSize) to follow the Rules of Hooks.
  • Use descriptive names that indicate what the hook does.
  • Group by domain, not by hook type (e.g., keep useCart and useCheckout together in a features/checkout/ folder).

📁 File Structure

Keep it organized like your other components or services:

src/
  hooks/
    useLocalStorage.ts
    useFetch.ts
    useDebounce.ts
  features/
    auth/
      useAuth.ts
    cart/
      useCart.ts

Rule of thumb: One hook per file. Keep each file focused and testable.

How to Write a Custom Hook

Let’s look at an example:

useDebounce.ts 

import { useEffect, useState } from 'react';

export function useDebounce<T>(value: T, delay: number): T {
  const [debounced, setDebounced] = useState(value);

  useEffect(() => {
    const timer = setTimeout(() => setDebounced(value), delay);
    return () => clearTimeout(timer);
  }, [value, delay]);

  return debounced;
}
  • Generic and reusable: Works with any value type.
  • Isolated: Only tracks debouncing logic.
  • Clean API: Easy to plug into any component.

Hook Design Best Practices

✅ Keep It Focused

One hook should do one thing well. Split up hooks like useForm and useValidation if they grow too complex.

✅ Avoid Side Effects in Return Values

Side effects (like triggering a fetch) should happen inside useEffect blocks, not directly in return values.

✅ Keep Hook Order Consistent

Never call hooks conditionally. This includes inside custom hooks—always ensure your hook calls happen in the same order every render.

✅ Type Everything

Use TypeScript to define clear input and output types for your hooks:

function useLocalStorage<T>(key: string, defaultValue: T): [T, (val: T) => void]

When Not to Use a Custom Hook

  • It’s used only once: If it’s not reused, don’t abstract it prematurely.
  • Too specific to one component: That logic might belong in the component or a service.
  • No lifecycle logic involved: Just extract a regular function or utility instead.

Using Custom Hooks Effectively

Composing Hooks

Hooks can call other hooks. For example, a useAuth hook might use useLocalStorage internally.

Example: useAuth.ts 

import { useState } from 'react';
import { useLocalStorage } from './useLocalStorage';

export function useAuth() {
  const [token, setToken] = useLocalStorage('auth_token', null);
  const [user, setUser] = useState(null);

  const login = (token: string, user: any) => {
    setToken(token);
    setUser(user);
  };

  return { token, user, login };
}

Optimization Tips

🧠 useMemo & useCallback

Use them inside your hook only when necessary to avoid unnecessary recalculations:

const memoizedValue = useMemo(() => compute(value), [value]);

👀 Avoid Over-Renders

Don’t put unnecessary values in your useEffect dependency array. Prefer memoized or stable references.

🧪 Test Your Hooks

Use libraries like @testing-library/react-hooks or vitest to test the logic in isolation.

Real World Strategy: Building a Hook Library

Once you’ve got multiple hooks, think modular:

  • Shared UI logic? → useMediaQuery, useModal, useToggle
  • App-specific logic? → useCart, useCheckout, useFeatureFlag
  • Domain-driven structure → Organize by app domain, not hook type.

Key Takeaways

✔ Custom hooks make logic reusable, clean, and testable.

✔ Keep each hook focused and one-per-file.

✔ Don’t abstract prematurely.

✔ Compose hooks wisely and avoid side effects in return values.

✔ Structure by feature domain, not by type.

✔ Type everything clearly with generics if needed.

✔ Test, optimize, and memoize when necessary.

Conclusion

Custom React hooks are a powerful abstraction when used wisely. By following these best practices—clear naming, focused design, thoughtful file organization, and selective optimization—you'll keep your codebase clean, maintainable, and scalable.

Have your own tips or favorite custom hook patterns? Share them in the comments!

Meta Description

A deep dive into best practices for custom React hooks: naming, structuring, when to use them, and how to avoid common pitfalls. Full guide with examples.

TLDR – Highlights for Skimmers

  • Custom hooks must start with use
  • One hook per file, organized by feature
  • Don’t call hooks conditionally or return side effects
  • Use TypeScript to type inputs and outputs
  • Only abstract when logic is reused or complex
  • Optimize with useMemo, useCallback where needed
  • Test in isolation for reliability