Vite

import { createContext, useContext, useEffect, useState } from "react"

type Theme = "dark" | "light" | "system"

type ThemeProviderProps = {
  children: React.ReactNode
  defaultTheme?: Theme
  storageKey?: string
}

type ThemeProviderState = {
  theme: Theme
  setTheme: (theme: Theme) => void
}

const initialState: ThemeProviderState = {
  theme: "system",
  setTheme: () => null,
}

const ThemeProviderContext = createContext<ThemeProviderState>(initialState)

export function ThemeProvider({
  children,
  defaultTheme = "system",
  storageKey = "vite-ui-theme",
  ...props
}: ThemeProviderProps) {
  const [theme, setTheme] = useState<Theme>(
    () => (localStorage.getItem(storageKey) as Theme) || defaultTheme
  )

  useEffect(() => {
    const root = window.document.documentElement

    root.classList.remove("light", "dark")

    if (theme === "system") {
      const systemTheme = window.matchMedia("(prefers-color-scheme: dark)")
        .matches
        ? "dark"
        : "light"

      root.classList.add(systemTheme)
      return
    }

    root.classList.add(theme)
  }, [theme])

  const value = {
    theme,
    setTheme: (theme: Theme) => {
      localStorage.setItem(storageKey, theme)
      setTheme(theme)
    },
  }

  return (
    <ThemeProviderContext.Provider {...props} value={value}>
      {children}
    </ThemeProviderContext.Provider>
  )
}

export const useTheme = () => {
  const context = useContext(ThemeProviderContext)

  if (context === undefined)
    throw new Error("useTheme must be used within a ThemeProvider")

  return context
}

import { ThemeProvider } from "@/components/theme-provider"

function App() {
  return (
    <ThemeProvider defaultTheme="dark" storageKey="vite-ui-theme">
      {children}
    </ThemeProvider>
  )
}

export default App

import { Moon, Sun } from "lucide-react"
import { Button } from "@/components/caprice-ui/button"
import * as Menu from "@/components/caprice-ui/menu"
import { useTheme } from "@/components/theme-provider"

export function ModeToggle() {
  const { setTheme } = useTheme()

  return (
    <Menu.Root>
      <Menu.Trigger
        render={
          <Button size="icon" variant="outline">
            <Sun className="dark:-rotate-90 h-[1.2rem] w-[1.2rem] rotate-0 scale-100 transition-all dark:scale-0" />
            <Moon className="absolute h-[1.2rem] w-[1.2rem] rotate-90 scale-0 transition-all dark:rotate-0 dark:scale-100" />
            <span className="sr-only">Toggle theme</span>
          </Button>
        }
      />
      <Menu.Portal>
        <Menu.Positioner align="end">
          <Menu.Popup>
            <Menu.Item onClick={() => setTheme('light')}>Light</Menu.Item>
            <Menu.Item onClick={() => setTheme('dark')}>Dark</Menu.Item>
            <Menu.Item onClick={() => setTheme('system')}>System</Menu.Item>
          </Menu.Popup>
        </Menu.Positioner>
      </Menu.Portal>
    </Menu.Root>
  )
}