How to Create Custom Hooks in React: A Quick Start Tutorial!

This developer-focused guide on How to Create Custom Hooks in React walks you through the logic, syntax, and real-world use cases of building reusable functionality in your React projects. Dive in for step-by-step instructions and performance tips.

React, developed by Meta (formerly Facebook), revolutionized front-end development with its declarative approach and powerful component architecture. With the introduction of hooks in React 16.8, managing state and side effects became more intuitive. But as applications grow, developers often find themselves repeating the same logic across multiple components. This is where custom hooks come into play.

In this comprehensive guide, you’ll learn how to create custom hooks in React, their purpose, structure, real-world examples, and implementation best practices. We’ll also dive into more advanced concepts and explore how custom hooks can be integrated into large-scale applications.

Let’s take the first step!

What is Hooks in React?

Custom hooks are special JavaScript functions in React that encapsulate and reuse logic across multiple components. They start with the prefix use, enabling them to call other hooks within their body. Think of custom hooks as tools to simplify and modularize your component logic, thereby enhancing maintainability.

Key Characteristics of Custom Hooks

• They follow the Rules of Hooks (e.g., call at the top level, only in function components).
• They can use other built-in hooks like useState, useEffect, useContext, etc.
• Their naming convention starts with use, like useState, useEffect, etc.
• They return stateful logic, values, or functions to the calling component.

Practical Use Case:

Imagine you’re tracking the browser window width in multiple components. Instead of duplicating useEffect and useState logic everywhere, create one custom hook useWindowWidth(), and reuse it.

// useWindowWidth.js
import { useState, useEffect } from 'react';

function useWindowWidth() {
  const [width, setWidth] = useState(window.innerWidth);

  useEffect(() => {
    const handleResize = () => setWidth(window.innerWidth);
    window.addEventListener('resize', handleResize);

    return () => window.removeEventListener('resize', handleResize);
  }, []);

  return width;
}

export default useWindowWidth;

Why Use Custom Hooks?

1. Avoid Code Duplication: In large applications, repeating logic across components leads to bloated code. Custom hooks centralize logic, making your codebase cleaner and easier to debug.
2. Promote Separation of Concerns: UI and logic can be separated. The component focuses only on rendering, while the hook handles the logic.
3. Encourage DRY Principle: DRY = Don’t Repeat Yourself. Custom hooks help enforce this principle and streamline logic.
4. Enable Unit Testing: You can test hooks independently using libraries like @testing-library/react-hooks.
5. Improve Readability: Cleaner components mean easier collaboration and faster onboarding for new developers.

How to Create Custom Hooks in React?

Let’s break down the process of building a custom hook from scratch.

Step 1: Identify Common Logic

Determine repeated logic across components. For example, data fetching, input validation, dark mode, or form handling.

Step 2: Create a Function That Starts with use

Example: useFetch, useForm, useAuth, etc.

import { useState, useEffect } from 'react';

function useFetch(url) {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);

  useEffect(() => {
    const fetchData = async () => {
      try {
        const response = await fetch(url);
        const result = await response.json();
        setData(result);
      } catch (err) {
        setError(err);
      } finally {
        setLoading(false);
      }
    };
    fetchData();
  }, [url]);

  return { data, loading, error };
}

export default useFetch;

Step 3: Use the Hook in Components

import useFetch from './useFetch';

function ProductList() {
  const { data, loading, error } = useFetch('/api/products');

  if (loading) return <p>Loading...</p>;
  if (error) return <p>Error: {error.message}</p>;

  return (
    <ul>
      {data.map(item => (
        <li key={item.id}>{item.name}</li>
      ))}
    </ul>
  );
}

Step 4: Modularize and Document

Add comments, JSDoc, or README files to describe each hook’s use and structure. Group similar hooks under a /hooks folder.

Real-World Custom Hook Examples

1. useDarkMode

Toggles dark/light themes based on user input or system preference.

import { useEffect, useState } from 'react';

function useDarkMode() {
  const [enabled, setEnabled] = useState(false);

  useEffect(() => {
    document.body.className = enabled ? 'dark-mode' : '';
  }, [enabled]);

  return [enabled, setEnabled];
}

2. useDebounce

Useful when dealing with search inputs or frequent API calls.

function useDebounce(value, delay) {
  const [debouncedValue, setDebouncedValue] = useState(value);

  useEffect(() => {
    const handler = setTimeout(() => {
      setDebouncedValue(value);
    }, delay);

    return () => clearTimeout(handler);
  }, [value, delay]);

  return debouncedValue;
}

3. useLocalStorage

Simplifies working with local storage.

function useLocalStorage(key, initialValue) {
  const [storedValue, setStoredValue] = useState(() => {
    try {
      const item = window.localStorage.getItem(key);
      return item ? JSON.parse(item) : initialValue;
    } catch (error) {
      return initialValue;
    }
  });

  const setValue = value => {
    try {
      const valueToStore = value instanceof Function ? value(storedValue) : value;
      setStoredValue(valueToStore);
      window.localStorage.setItem(key, JSON.stringify(valueToStore));
    } catch (error) {
      console.error(error);
    }
  };

  return [storedValue, setValue];
}

Best Practices for Writing Custom Hooks

• Avoid Conditional Hook Calls: Always call hooks at the top level.
• Return Meaningful Data/Functions: Don’t return JSX, only return logic.
• Combine Related Hooks: Group useEffect, useState, etc., that serve a shared purpose.
• Test Your Hooks: Use unit testing for logic isolation.
• Name Clearly: Your hook’s name should indicate its purpose, e.g., useIsOnline, useCountdown, etc.

Integrating Custom Hooks in Large Projects

When building enterprise-level apps:

• Group hooks under src/hooks.
• Use TypeScript to define types and improve reliability.
• Use ESLint + Prettier for consistency.
• Create custom hook libraries for teams to reuse across projects.

If you’re looking for a structured and beginner-friendly video course that also covers custom hooks in-depth, we highly recommend checking out this free YouTube tutorial:

This comprehensive course is perfect for beginners and intermediate developers alike who want to strengthen their React skills with practical projects.

FAQs:)

Conclusion:)

Understanding how to create custom hooks in React is a fundamental skill for modern front-end developers. It not only improves the readability and maintainability of your code but also enforces modular development practices that scale.

Custom hooks help you encapsulate business logic, make your UI components cleaner, and foster reusability. As your React applications grow, investing time in creating and maintaining a collection of well-documented custom hooks will pay off in productivity and code quality.

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We hope this guide has helped you gain clarity and confidence in building your hooks. If you found this article helpful or have any questions, thoughts, or experiences to share, we’d love to hear from you—feel free to leave a comment below!