2025-12-30

Generated at: 2025-12-30T20:26:31.862Z

React Frontend Engineering Note: Custom Hooks

Concept

Custom Hooks are a powerful feature in React that allows you to encapsulate reusable logic inside a function. They are a way to reuse stateful logic without changing the component hierarchy. Custom hooks can utilize built-in hooks (like useState and useEffect) or can be composed of other custom hooks, making them highly versatile.

When to Use It

Use Custom Hooks when:

• You have reusable logic that you want to share across multiple components.
• You want to keep your components clean and focused on rendering UI.
• You need to enhance reusability and maintainability in your codebase.

Small Example

Here’s a simple custom hook that manages a form input:

// useInput.js
import { useState } from 'react';

function useInput(initialValue) {
  const [value, setValue] = useState(initialValue);

  const handleChange = (event) => {
    setValue(event.target.value);
  };

  return {
    value,
    onChange: handleChange,
  };
}

export default useInput;

Now, you can use this useInput hook in any component:

// FormComponent.js
import React from 'react';
import useInput from './useInput';

function FormComponent() {
  const name = useInput('');
  const email = useInput('');

  const handleSubmit = (event) => {
    event.preventDefault();
    alert(`Name: ${name.value}, Email: ${email.value}`);
  };

  return (
    <form onSubmit={handleSubmit}>
      <div>
        <label>Name:</label>
        <input type="text" {...name} />
      </div>
      <div>
        <label>Email:</label>
        <input type="email" {...email} />
      </div>
      <button type="submit">Submit</button>
    </form>
  );
}

export default FormComponent;

By using the useInput custom hook, we’ve streamlined the handling of input state in FormComponent, making our code cleaner and more reusable.