Dark mode in Vite-React

Here's how you can add dark mode to your Vite-React application.

Create a theme provider

Create a theme-provider.tsx file and paste the below code in it

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;
};

Expand

Wrap the root layout of your application

Wrap your application with the ThemeProvider component.

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

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

export default App;

Create a toggle button

Create a toggle button to switch between light and dark themes.

import { MoonIcon, SunIcon } from "@astraicons/react/linear";
import { Button } from "@/app/common/astra-ui/button";
import { useTheme } from "./theme-provider";

const ThemeButton = () => {
  const { theme, setTheme } = useTheme();

  return (
    <Button
      className="flex-shrink-0 p-2.5 ring-0 focus:ring-0 focus:border-none text-grayscale-textIcon-title"
      variant="ghost"
      size="md"
      onClick={() => setTheme(theme === "light" ? "dark" : "light")}
    >
      <SunIcon className="size-6 transition-all scale-100 rotate-0 dark:-rotate-90 dark:scale-0" />
      <MoonIcon className="absolute size-6 transition-all scale-0 rotate-90 dark:rotate-0 dark:scale-100" />
      <span className="sr-only">Toggle theme</span>
    </Button>
  );
};

export default ThemeButton;

Expand

Now you can use this switch in your application to toggle between light and dark themes.