Easy way to use Dark Mode in Next.js + Tailwind

#nextjs #css #react #javascript

Yesterday I was working on my personal website, and I really wanted to add a dark mode toggle.
I already converted my site to use Tailwind before, so how do I enable dark mode now?

It's simple: in Tailwind v2 dark mode is built in (https://tailwindcss.com/docs/dark-mode).

To be able to toggle the dark mode, you should put darkMode: 'class' in your tailwind.config.js.
This configuration implies that a class called dark will be added to the <html> tag.
Once this class is active, your dark:{class} classes will become active.

To link this functionality up with Next.js I used the lightweight next-themes library (https://github.com/pacocoursey/next-themes).

After installing this library, simply change your _app.js to include the ThemeProvider:

import { ThemeProvider } from 'next-themes'

function MyApp({ Component, pageProps }) {
  return (
    <ThemeProvider attribute="class">
      <Component {...pageProps} />
    </ThemeProvider>
  )
}

export default MyApp

Including the attribute="class" is very important, since this tells the library to use the Tailwind dark theme class.

For the toggle button I used the following:

import {useTheme} from 'next-themes'

const {theme, setTheme} = useTheme()

<button
  aria-label="Toggle Dark Mode"
  type="button"
  className="p-3 h-12 w-12 order-2 md:order-3"
  onClick={() => setTheme(theme === 'dark' ? 'light' : 'dark')}
>

An example of the dark:{class} code, this will use a purple background color for light mode and a darkgrey color for dark mode:

<nav className="fixed bg-purple dark:bg-darkgrey h-16 w-full z-50">

And that's it! The theme is being switched when you click the button.
Live example can be found here: https://www.thomasledoux.be/
Github source: https://github.com/thomasledoux1/website-thomas
Inspired by: https://leerob.io

Discussion (16)

Shrihari Mohan • Feb 19

Was new to react & next , was confused with using contexts on _document.tsx , because at the tailwind docs it said add class to HTML.
This is a life saver. ♥️

So i went to docs of next-theme. and missed the attribute = class part (wasted 10 mins of life)

By the way , Thanks , really appreciate it.

David Dal Busco • Jan 21 '21

Next + Tailwind = Sweet tech stack!

Thanks for the share Thomas 👍

Thomas Ledoux • Jan 21 '21

I couldn't agree more :)
My pleasure!

David Dal Busco • Feb 12 '21

I know it was a good idea to keep your post on the side, just used it 😉

Thx again Thomas!

Thomas Ledoux • Feb 12 '21

Excited to see the result!

Md F A Sadik • Feb 14

Thanks for sharing the wonderful idea ❤️

Thomas Ledoux • Feb 15

You're welcome!

Rishav Jadon • Jan 12 • Edited on Jan 12

I have done everything said here, and i still cannot see the dark mode happening. It changes if I set my system to dark mode, but I've set the darkMode property in tailwind.config.js to "class". Been googling for hours :(

Thomas Ledoux • Jan 12

Hi Rishav, do you have a repository/codesandbox I can check out?

Rishav Jadon • Jan 13

Yes, here: github.com/rjitsu/cssKenpai-v2

Thomas Ledoux • Jan 13

I think you could move the ThemeProvider in github.com/rjitsu/cssKenpai-v2/blo... to the top level of the rendering. Maybe that might help to get the <div className="dark:bg-gray-700"> part working?

Rishav Jadon • Jan 13

Great, that fixed it, thanks so much! I thought the ThemeProvider could only have Component as it's children, that's why I didn't try this yet. Thanks.