React-css-theme-switcher NPM

💫 Switch between CSS themes using React

Prerequisites

node >=10

Installation

npm i react-css-theme-switcher

or with Yarn:

yarn add react-css-theme-switcher

Usage

Import ThemeSwitcherProvider and pass a theme object with the names of the themes and their respective paths to the CSS stylesheet (normally, public folder).

import React from 'react';
import ReactDOM from 'react-dom';

import { ThemeSwitcherProvider } from 'react-css-theme-switcher';

const themes = {
  light: 'public/light.css',
  dark: 'public/dark.css',
};

const App = () => {
  return (
    <ThemeSwitcherProvider defaultTheme="light" themeMap={themes}>
      <Component />
    </ThemeSwitcherProvider>
  );
};

Use useThemeSwitcher Hook:

import { useThemeSwitcher } from 'react-css-theme-switcher';

const Component = () => {
  const { switcher, themes, currentTheme, status } = useThemeSwitcher();
  const [isDarkMode, setIsDarkMode] = React.useState(false);

  if (status === 'loading') {
    return <div>Loading styles...</div>;
  }

  const toggleDarkMode = () => {
    setIsDarkMode(previous => {
      switcher({ theme: previous ? themes.light : themes.dark });
      return !previous;
    });
  };

  return (
    <div>
      <h2>Current theme: {currentTheme}</h2>
      <button onClick={toggleDarkMode} />
    </div>
  );
};

CSS Injection Order

react-css-theme-switcher provides a way to avoid collision with other stylesheets or appended styles by providing where to inject the styles. To achieve this, add an HTML comment like  somewhere on the head and then provide 'inject-styles-here' or your custom name in the insertionPoint prop in ThemeSwitcherProvider.

<!DOCTYPE html>
<html lang="en">
  <head>
    <style>
      @import url('https://fonts.googleapis.com/css2?family=Poppins&display=swap');

      * {
        color: inherit;
      }

      html {
        font-family: 'Poppins', sans-serif;
      }
    </style>
    <!-- inject-styles-here -->
    <title>Playground</title>
  </head>

  <body>
    <div id="root"></div>
  </body>
</html>

const App = () => {
  return (
    <ThemeSwitcherProvider
      defaultTheme="light"
      insertionPoint="inject-styles-here"
      themeMap={themes}
    >
      <Component />
    </ThemeSwitcherProvider>
  );
};

HTML Element Insertion Point

Some libraries and frameworks make it hard to use comments in head for handling injection order. To solve this issue, you can provide a DOM element as the insertion point. Take for example a <noscript></noscript> element:

<!DOCTYPE html>
<html lang="en">
  <head>
    <style>
      @import url('https://fonts.googleapis.com/css2?family=Poppins&display=swap');

      * {
        color: inherit;
      }

      html {
        font-family: 'Poppins', sans-serif;
      }
    </style>
    <noscript id="inject-styles-here"></noscript>

    <title>Playground</title>
  </head>

  <body>
    <div id="root"></div>
  </body>
</html>

const App = () => {
  return (
    <ThemeSwitcherProvider
      defaultTheme="light"
      insertionPoint={document.getElementById('inject-styles-here')}
      themeMap={themes}
    >
      <Component />
    </ThemeSwitcherProvider>
  );
};

API

ThemeSwitcherProvider

Props

Name	Type	Default value	Description
attr	String	data-theme	Attribute name for that will be appended to the body tag. Its value will be the current theme name.
defaultTheme	String		Default theme to load on mount. Must be in themeMap
id	String	current-theme-style	Id of the current selected CSS.
insertionPoint	String or HTMLElement		Comment string or element where pre-fetch styles and current themes will be injected. The library will look for the comment string inside head element. If missing will append styles at the end of the head. This is useful for CSS override.
themeMap	Object		Object with all themes available. Key is the theme name and the value is the path for the CSS file.

useThemeSwitcher

Returns

Name	Type	Default value	Description
currentTheme	String or Undefined	undefined	Current selected theme
themes	Object	themeMap keys	All themes supplied in the themeMap.
switcher	({ theme }: { theme: string }) => void;	Function	Function to change themes.
status	enum('idle', 'loading', 'loaded')	idle	Current load status of the selected stylesheet. Useful to prevent flicker when changing themes.