react-dual-theme

A dual theme context for React (Native) apps to support dark mode purposes.

✨ Installation

Install package:

yarn add react-dual-theme

or

npm install react-dual-theme

---

📖 Reference

ThemeProvider

A component used to set theme for its children.

Prop	Type	Required
theme	string or [string, string]	yes

Passing a single string to the theme prop is considered same as passing a tuple of the same string as [string, string].

useTheme(): [string, string]

A React hook to be used in functional components to get theme from the nearest ThemeProvider parent.

Returns tuple of strings.

#	Type	Description
[0]	string	First theme name
[1]	string	Second theme name

---

🚀 Usage

1. Wrap your app in <ThemeProvider>...</ThemeProvider>:

// ./App.js
// Example with Dark Mode
import { ThemeProvider } from 'react-dual-theme'
import { DarkModeProvider } from 'react-native-dark-mode'

import { Text, View } from './ThemedComponents'

const App = () => {
  return (
    <DarkModeProvider>
      <ThemeProvider theme={['red-on-light', 'red-on-dark']}>
        <View>
          <Text>Hello themed text!</Text>
        </View>
      </ThemeProvider>
    </DarkModeProvider>
}

2. Create component to consume the theme context:

// ./ThemedComponents.js
// @flow
import * as React from 'react'
import {
  StyleSheet,
  View as RNView,
  Text as RNText,
} from 'react-native'
import { useTheme } from 'react-dual-theme'
import { useDarkMode } from 'react-native-dark-mode'

const viewStyles = StyleSheet.create({
  'red-on-dark': { backgroundColor: 'black' },
  'red-on-light': { backgroundColor: 'white' },
})

// Type just for example purposes:
declare type Style = null | Object | (null | Object | Style)[];

type Props = {
  children?: React.Node,
  style?: Style,
}

export const View = ({ children, style, ...rest }: Props) => {
  const [light, dark] = useTheme()
  const isDarkMode: boolean = useDarkMode()

  // Add some theming logic..
  const themeStyle = isDarkMode ? viewStyles[dark] : viewStyles[light]

  return <RNView
    {...rest}
    style={[themeStyle, style]}
  >
    {children}
  </RNView>
}

const textStyles = StyleSheet.create({
  'red-on-dark': { color: 'red' },
  'red-on-light': { color: 'red' },
})

export const Text = ({ children, style, ...rest }: Props) => {
  const [light, dark] = useTheme()
  const isDarkMode: boolean = useDarkMode()

  // Add some theming logic..
  const themeStyle = isDarkMode ? textStyles[dark] : textStyles[light]

  return <RNText
    {...rest}
    style={[themeStyle, style]}
  >
    {children}
  </RNText>
}

3. Extra: View as a ThemeProvider

You can simply make a <View /> component a theme provider in the same time:

import { ThemeProvider, useTheme } from 'react-dual-theme'

type Props = {
  children?: React.Node,
  style?: Style,
  theme: string | [string, string],
}

export const View = ({ children, style, theme, ...rest }: Props) => {
  const Component = <RNView
      // ...
    />

  return theme // Provide new theme context when needed
    ? <ThemeProvider theme={theme}><Component /></ThemeProvider>
    : <Component />
}

---

🔧 Using Flow definitions & Setting up your .flowconfig

This package has .js.flow files to let Flow use type definitions. However, most projects ignore everything under node_modules to skip type-checking dependencies.

To be able to use types included inside of packages, consider moving <PROJECT_ROOT>/node_modules/.* from [ignore] to [untyped] section. This way Flow can wak through the node_modules but exports as any.

Best part is you don't need to generate empty definitions using flow-typed create-stub anymore.

Edit your .flowconfig

1. Remove node_modules from the [ignore] section:

   [ignore]
   ; <PROJECT_ROOT>/node_modules/.* ; <<< you should not need this

2. Add node_modules to [untyped] section:

   [untyped]
   <PROJECT_ROOT>/node_modules/.* ; <<< export every module as any by default
   !<PROJECT_ROOT>/node_modules/react-dual-theme/.* ; <<< exception

3. Add react-dual-theme to [declarations] section:

   [declarations]
   <PROJECT_ROOT>/node_modules/react-dual-theme/.* ; <<< use types from .flow.js files

4. Flow should be now able to get through the package typings.

5. Profit 🎉

---

🚧 Typescript (needs testing)

This package includes TypeScript definition index.d.ts file.

---

Licence: MIT

@martin_adamko 🐤