Persist State to Local Storage with useLocalStorage Hook

import React, { useState, useEffect } from 'react';

// Custom hook for persisting state to localStorage
function useLocalStorage(key, initialValue) {
  // State to store our value
  // Pass initial state function to useState so logic is only executed once
  const [storedValue, setStoredValue] = useState(() => {
    try {
      const item = window.localStorage.getItem(key);
      return item ? JSON.parse(item) : initialValue;
    } catch (error) {
      console.error("Error reading from localStorage:", error);
      return initialValue;
    }
  });

  // useEffect to update local storage when the state changes
  useEffect(() => {
    try {
      window.localStorage.setItem(key, JSON.stringify(storedValue));
    } catch (error) {
      console.error("Error writing to localStorage:", error);
    }
  }, [key, storedValue]); // Re-run if key or storedValue changes

  return [storedValue, setStoredValue];
}

// Example component using the custom hook
function UserSettings() {
  const [theme, setTheme] = useLocalStorage('appTheme', 'light');
  const [userName, setUserName] = useLocalStorage('userName', '');

  const toggleTheme = () => {
    setTheme(prevTheme => (prevTheme === 'light' ? 'dark' : 'light'));
  };

  return (
    <div style={{ padding: '20px', background: theme === 'dark' ? '#333' : '#f0f0f0', color: theme === 'dark' ? '#fff' : '#333' }}>
      <h1>User Settings</h1>
      <p>Current Theme: {theme}</p>
      <button onClick={toggleTheme}>Toggle Theme</button>
      <hr />
      <label>
        Your Name:
        <input
          type="text"
          value={userName}
          onChange={(e) => setUserName(e.target.value)}
          style={{ marginLeft: '10px', padding: '5px' }}
        />
      </label>
      <p>Hello, {userName || 'Guest'}!</p>
      <p><em>Refresh the page to see state persistence.</em></p>
    </div>
  );
}

export default UserSettings;