my-links/inertia/contexts/dark_theme_context.tsx

import { usePage } from '@inertiajs/react';
import { ReactNode, createContext, useEffect, useState } from 'react';
import { tuyau } from '~/lib/tuyau';

const LS_KEY = 'dark_theme';

export const DarkThemeContext = createContext({
	isDarkTheme: true,
	toggleDarkTheme: (_value: boolean) => {},
});

export default function DarkThemeContextProvider({
	children,
}: {
	children: ReactNode;
}) {
	const { preferDarkTheme } = usePage<{ preferDarkTheme: boolean }>().props;
	const [isDarkTheme, setDarkTheme] = useState<boolean>(preferDarkTheme);
	const toggleDarkTheme = (value: boolean) => {
		setDarkTheme(value);
		tuyau.user.theme.$post({
			preferDarkTheme: value,
		});
	};

	useEffect(() => {
		localStorage.setItem(LS_KEY, String(isDarkTheme));
	}, [isDarkTheme]);

	return (
		<DarkThemeContext.Provider
			value={{
				isDarkTheme,
				toggleDarkTheme,
			}}
		>
			{children}
		</DarkThemeContext.Provider>
	);
}