Usage

React

import { createContext, useContext, useState, type ReactNode } from 'react';
import Darkify, { type Options } from 'darkify-js';

const options: Partial<Options> = {
  autoMatchTheme: true,
  // useLocalStorage: default is true
  // useSessionStorage: default is false
  // useColorScheme: default is ['#ffffff', '#000000']
}

let d = new Darkify('', options);

const ThemeContext = createContext<{
  theme: string;
  toggleTheme: () => void;
} | null>(null);

export const ThemeProvider = ({ children }: { children: ReactNode }) => {
  const [theme, setTheme] = useState<string>(() => d.getCurrentTheme());

  const toggleTheme = () => {
    d.toggleTheme();
    setTheme(d.getCurrentTheme());
  };

  return (
    <ThemeContext.Provider value={{ theme, toggleTheme }}>
      {children}
    </ThemeContext.Provider>
  );
};

export const useTheme = () => {
  const context = useContext(ThemeContext);
  if (!context) {
    throw new Error('useTheme must be used within a ThemeProvider');
  }
  return context;
};

React + Zustand

import { create } from 'zustand';
import Darkify, { type Options } from 'darkify-js';

const options: Partial<Options> = {
  autoMatchTheme: true,
  // useLocalStorage: default is true
  // useSessionStorage: default is false
  // useColorScheme: default is ['#ffffff', '#000000']
}

let d = new Darkify('', options);

const useThemeStore = create<{
  theme: string;
  toggleTheme: () => void;
}>((set) => ({
  theme: d.getCurrentTheme(),
  toggleTheme: () => {
    d.toggleTheme();
    set({ theme: d.getCurrentTheme() });
  },
}));

export default useThemeStore;

TailwindCSS

v3.x

// tailwind.config.js
darkMode: ['selector', '[data-theme="dark"]']

v4.x

@import "tailwindcss";

@custom-variant dark (&:where([data-theme=dark], [data-theme=dark] *));

@theme {
  --color-background: #fff;
  --color-foreground: #000;
}

@variant dark {
  --color-background: #000;
  --color-foreground: #fff;
}

@layer base {
  html,
  body {
    @apply bg-background text-foreground;
  }
}