Radix UI + Next.js Light/Dark Mode Toggle

I'm trying to implement a light vs dark mode toggle for my Next app. I'm using the radix ui component library for my styling. I'm a little stuck trying to figure out the logic to make this happen. How can I add this functionality to my Navbar if I have to declare the theme inside of my layout.tsx file?

layout.tsx: layout

NavBar.tsx: navbar

Solution

Step 1: Install next-themes

npm install next-themes

Step 2: Create a theme provider

"use client"

import * as React from "react"
import { ThemeProvider } from "next-themes"

export function ThemeProvider({ children, ...props }) {
  return <ThemeProvider {...props}>{children}</ThemeProvider>
}

Step 3: Wrap your root layout

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

export default function RootLayout({ children }) {
  return (
    <>
      <html lang="en" suppressHydrationWarning>
        <head />
        <body>
          <ThemeProvider
            attribute="class"
            defaultTheme="system"
            enableSystem
            disableTransitionOnChange
          >
            {children}
          </ThemeProvider>
        </body>
      </html>
    </>
  )
}

Step 4: Add a mode toggle

"use client"

import * as React from "react"
import { useTheme } from "next-themes"

export function NavBar() {

  const { theme, setTheme } = useTheme()
  const toggleMode = () => setTheme(theme == 'light' ? 'dark' : 'light')
  
  return (
    <>
    {/* Your code for the navbar */}
      <button onClick={toggleMode}> Toggle mode </button>
    </>
  )
}