Dependent types for https://github.com/JoseRFelix/react-css-theme-switcher

react-css-theme-switcher.ts

import React from 'react';

type DeferTypeInference<T> = [T][T extends any ? 0 : never];

interface Props<T extends string> {
  themeMap: Record<T, any>
  defaultTheme?: DeferTypeInference<T>;
}

class ThemeSwitcherProvider<T extends string> extends React.Component<Props<T>> { }

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

<ThemeSwitcherProvider defaultTheme="dark" themeMap={themes} />