Remix Themes

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Features

- ✅ Perfect dark mode in a few lines of code
- ✅ System setting with prefers-color-scheme
- ✅ No flash on load
- ✅ Disable flashing when changing themes
- ✅ Class or data attribute selector
- ✅ Sync theme across tabs and windows

Check out the
Example
to see it in action.

If you are using Remix.run you can use v1.6.1 of this library or lower, v2 onwards is only react-router v7 compatible.

Install

``bash
$ npm install remix-themes


or


$ yarn add remix-themes
`

Getting Started

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`ts
// sessions.server.tsx

import { createThemeSessionResolver } from "remix-themes";
import { createCookieSessionStorage } from "react-router";

const sessionStorage = createCookieSessionStorage({
cookie: {
name: "__remix-themes",
// domain: 'remix.run',
path: "/",
httpOnly: true,
sameSite: "lax",
secrets: ["s3cr3t"],
// secure: true,
},
});

export const themeSessionResolver = createThemeSessionResolver(sessionStorage);
`

Note: make sure you have domain and secure parameters set only for your
production environment. Otherwise, Safari won't store the cookie if you set
these parameters on localhost.

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`ts
// root.tsx

import {
ThemeProvider,
useTheme,
PreventFlashOnWrongTheme,
} from "remix-themes";
import { themeSessionResolver } from "./sessions.server";

// Return the theme from the session storage using the loader
export const loader: LoaderFunction = async ({ request }) => {
const { getTheme } = await themeSessionResolver(request);
return {
theme: getTheme(),
};
};

// Wrap your app with ThemeProvider.
// specifiedTheme is the stored theme in the session storage.
// themeAction is the action name that's used to change the theme in the session storage.
export default function AppWithProviders() {
const data = useLoaderData();
return (



);
}

// Use the theme in your app.
// If the theme is missing in session storage, PreventFlashOnWrongTheme will get
// the browser theme before hydration and will prevent a flash in browser.
// The client code runs conditionally, it won't be rendered if we have a theme in session storage.
function App() {
const data = useLoaderData();
const [theme] = useTheme();
return (














);
}
`

#### Add the action route

Create a file in /routes/action/set-theme.ts or /routes/action.set-theme.ts
when using
Route File Naming v2
with the content below. Ensure that you pass the filename to the ThemeProvider
component.

> Note: You can name the action route whatever you want. Just make sure you pass
> the correct action name to the ThemeProvider component. Make sure to use
> absolute path when using nested routing.

This route is used to store the preferred theme in the session storage when
the user changes it.

`ts
import { createThemeAction } from "remix-themes";
import { themeSessionResolver } from "./sessions.server";

export const action = createThemeAction(themeSessionResolver);
`

API

Let's dig into the details.

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- specifiedTheme: The theme from the session storage.
- themeAction: The action name used to change the theme in the session
storage.
- disableTransitionOnThemeChange: Disable CSS transitions on theme change to
prevent the flashing effect.

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useTheme takes no parameters but returns:

- theme: Active theme name
- setTheme: Function to set the theme. If the theme is set to null, the
system theme will be used and definedBy property in the metadata object
will be set to SYSTEM.
- metadata: An object which contains the following properties:
- definedBy: The theme source. It can be USER or SYSTEM. Useful to
detect if the theme was set by the user or by the system.

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createThemeSessionResolver function takes a cookie session storage and returns

- resolver: A function that takes a request and returns an object with the
following properties:
- getTheme: A function that returns the theme from the session storage.
- setTheme: A function that takes a theme name and sets it in the session
storage.
- commit: A function that commits the session storage (Stores all data in
the session and returns the Set-Cookie header to use in the HTTP response.)

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On the server, "theme" might be null so PreventFlashOnWrongTheme ensures
that this is correct before hydration. If the theme is null on the server, this
component will set the browser theme on the html element in a data-theme
attribute if exists, otherwise it will be set to a class attribute. If both
data-theme and class are set, the data-theme will be used.

- ssrTheme`: boolean value that indicates if we have a theme in the session
storage.