This is working example of theme switcher in ReactJS by using Context API Hook and CSS Variables.
/Context: where we created the context
/HomePage: For Home-page
/Context/ThemeContext.js : This file has the context of the theme
App.js : App.js has the provider of the theme and handling the logic of toggling the theme
App.css: CSS Variables for the theme
We build a theme switcher in a React app using the useContext hook and the Context API. We implemented a theme context provider, created the necessary components, and updated the styles based on the selected theme. With this implementation, users can easily switch between different themes and update the background color of the app.