ReactHooks.dev

useHooks()

useTheme

2020-04-13 Anthony HumphreysUI

Recently I was working on a React Native project and I was asked to come up with an a dark theme for the app and make that the default, with an option for the user to switch to light theme at any time without having to restart the app (looking at you Microsoft Teams…). In order to do this, and to tidy up the styling of the app in general, I decided to create a theme context for the app. We are using vanilla React Native styling for this project, so I decided to roll my own theme context provider solution.

Context Provider

For my use case I came up with the following provider:

interface IThemeContext {
  theme: Theme;
  activeTheme: Mode;
  setTheme: Function;
}

export default createContext<IThemeContext>({
  theme: lightTheme,
  activeTheme: null,
  setTheme: (mode: Mode) => null
});

theme being the object representing the currently active theme.

activeTheme is an enum, Mode which is either DARK or LIGHT.

setTheme calls a setter for a useState hook which drives the value of theme based on the current Mode.

The code for the actual hook is actually quite simple, and arguably unnecessary, though it avoids me having to repeatedly import and use a context provider, and allows for some future functionality.

export default function useTheme() {
  const { theme } = useContext(themeContext);
  return theme;
}
  • © Anthony Humphreys 2020