Theming

Theming in Unistyles differs from other libraries as it doesn’t impose any specific syntax.

Any JavaScript object can be a Unistyles theme.

There is also no limit to the number of themes. You can even register dozens of them, for example, if your app sells some premium ones.

Theming is optional. If you dont’t register themes with UnistylesRegistry the library will use an empty object by default.

Create a theme

You can organize your themes however you want:

const myTheme = {
    // any keys
    colors: {
        // your colors
    },
    components: {
        // any number of nesting
        button: {
            deepKey: {}
        }
    },
    utils: {
        // you can even use functions here
        hexToRGBA: () => {}
    },
    // or compute your themes with functions and spread operators
    ...premiumFeatures,
    ...getMyColors()
}

If you use TypeScript you need to override the library’s type:

type AppThemes = {
  name: typeof myTheme
}

declare module 'react-native-unistyles' {
  export interface UnistylesThemes extends AppThemes {}
}

Finally, to register the theme, you need to call UnistylesRegistry:

import { UnistylesRegistry } from 'react-native-unistyles'
import { myTheme } from './themes'

UnistylesRegistry
    .addThemes({
        name: myTheme,
        // you can add more themes here
    })

Where name is the unique name of your theme.

Tip

Your themes may have different shapes, but it’s generally not recommended.

Select theme

If you’ve registered more than one theme, Unistyles won’t know which one is the initial one. At this point, you have 3 options:

• If you know the initial theme upfront, select it with addConfig from UnistylesRegistry

UnistylesRegistry
    .addThemes({
        light: myTheme,
        premium: premiumTheme
    })
    .addConfig({
        initialTheme: 'premium'
    })

• If you need to resolve the user-selected theme during runtime, call useInitialTheme before using your first useStyles hook:

import { useInitialTheme, useStyles } from 'react-native-unistyles'

// can be read from any storage eg. MMKV/SQL/FileSystem/Appearance
const userTheme = ...

useInitialTheme(userTheme)

// useInitialTheme must be called before the first useStyles hook
// it's so fast that you can even call it in the same component!
const { styles } = useStyles(stylesheet)

• Use adaptive themes, as mentioned below

Danger

Without a selected theme, Unistyles will throw an error:

“Your themes are registered, but you didn’t select the initial theme”

Get the current theme

To get the current theme, you can either obtain it from the useStyles hook:

const { theme } = useStyles()

or access it in the createStyleSheet function:

const stylesheet = createStyleSheet(theme => ({
    ...
}))

Get the current theme name

To get the current theme name, import UnistylesRuntime:

import { UnistylesRuntime } from 'react-native-unistyles'

// access the current theme name in your component
export const UserTheme = () => (
    <Text>
        Selected theme is {UnistylesRuntime.themeName}
    </Text>
)

Adaptive themes

Adaptive themes allow Unistyles to automatically manage the selection of your themes based on device scheme settings. To enable this, you need to meet two conditions:

• register two themes with reserved names light and dark:

UnistylesRegistry
    .addThemes({
        light: lightTheme,
        dark: darkTheme,
        // you may have more themes
    })

• Explicitly enable adaptiveThemes:

UnistylesRegistry
    .addThemes({
        light: lightTheme,
        dark: darkTheme,
        // you may have more themes
    })
    .addConfig({
        adaptiveThemes: true
    })

Toggle adaptive themes during runtime

To toggle adaptive theme support at any point, use UnistylesRuntime:

import { UnistylesRuntime } from 'react-native-unistyles'

// toggle support for adaptive themes at any point
export const ToggleAdaptiveThemes = () => (
    <Button
        title="Disable adaptive themes"
        onPress={() => UnistylesRuntime.setAdaptiveThemes(false)}
    />
)

Check if adaptive themes are enabled

To check if adaptive themes are enabled, again use UnistylesRuntime:

import { UnistylesRuntime } from 'react-native-unistyles'

// check if you've enabled adaptive themes
export const AdaptiveThemes = () => (
    <Text>
        Adaptive themes are {UnistylesRuntime.hasAdaptiveThemes ? 'enabled' : 'disabled'}
    </Text>
)

Get device color scheme

Check your device color preference with UnistylesRuntime:

import { UnistylesRuntime } from 'react-native-unistyles'

// check the current device scheme preference
export const UserTheme = () => (
    <Text>
        My device is using the {UnistylesRuntime.colorScheme} scheme.
    </Text>
)

Available options are: dark, light or unspecified for devices that don’t support color schemes.

Caution

Unistyles will read your device settings, not user preferences. It’s not compatible with the React Native Appearance module.

If your app’s theme is not changing based on device settings, please refer to the FAQ

Change theme

With Unistyles 2.0, we no longer use a React Context. However, this doesn’t mean you can’t change the theme. In fact, it’s even easier as you don’t need to re-render the entire app. To change the theme at any time, simply call setTheme function:

import { UnistylesRuntime } from 'react-native-unistyles'

// change the theme in any component
export const ChangeTheme = () => (
    <Button
        title="Change theme"
        onPress={() => UnistylesRuntime.setTheme('dark')}
    />
)

UnistylesRuntime

UnistylesRuntime is a powerful feature, and you can learn more about it here.