VueUse

useDark

Reactive dark mode with auto data persistence.

Basic Usage 

import { useDark, useToggle } from '@vueuse/core'

const isDark = useDark()
const toggleDark = useToggle(isDark)

Behavior

useDarkcombines with usePreferredDarkand useStorage On start up, it reads the value from localStorage/sessionStorage(the key is configurable) to see if there is user configured color scheme, if not, it will use users' system preferences. When you change the isDark ref, it will update the corresponding element's attribute and then store the preference to storage for persistence.

Please note useDarkonly handles the DOM attribute changes for you to apply proper selector in your CSS. It does NOT handle the actual style, theme or CSS for you.

Configuration

By default, it uses Tailwind CSS favored dark mode, which enables dark mode when class dark is applied to the html tag, for example:

<!--light-->
<html> ... </html>

<!--dark-->
<html class="dark"> ... </html>

While you can customize it and make it works for most the of the CSS frameworks.

For example:

const isDark = useDark({
  selector: 'body',
  attribute: 'color-scheme',
  valueDark: 'dark',
  valueLight: 'light'
})

will works like

<!--light-->
<html>
  <body color-scheme="light"> ... </body>
</html>

<!--dark-->
<html>
  <body color-scheme="dark"> ... </body>
</html>

If the configuration above still not fitting to your needs, you can use onChanged options to take ful controls over how you handle the updates

const isDark = useDark({
  onChanged(dark: boolean) {
    // update the dom, call the API or something
  }
})

Component 

<UseDark v-slot="{ isDark, toggleDark }">
  <button @click="toggleDark()">
    Is Dark: {{ isDark }}
  </button>
</UseDark>

Type Declarations 

export declare type ColorSchemes = "light" | "dark" | "auto"
export interface UseDarkOptions extends StorageOptions<ColorSchemes> {
  /**
   * CSS Selector for the target element applying to
   *
   * @default 'html'
   */
  selector?: string
  /**
   * HTML attribute applying the target element
   *
   * @default 'class'
   */
  attribute?: string
  /**
   * Value applying to the target element when isDark=true
   *
   * @default 'dark'
   */
  valueDark?: string
  /**
   * Value applying to the target element when isDark=false
   *
   * @default ''
   */
  valueLight?: string
  /**
   * A custom handler for handle the updates.
   * When specified, the default behavior will be overridded.
   *
   * @default undefined
   */
  onChanged?: (isDark: boolean) => void
  /**
   * Key to persist the data into localStorage/sessionStorage.
   *
   * Pass `null` to disable persistence
   *
   * @default 'vueuse-color-scheme'
   */
  storageKey?: string | null
  /**
   * Storage object, can be localStorage or sessionStorage
   *
   * @default localStorage
   */
  storage?: StorageLike
}
/**
 * Reactive dark mode with auto data persistence.
 *
 * @see https://vueuse.org/useDark
 * @param options
 */
export declare function useDark(
  options?: UseDarkOptions
): WritableComputedRef<boolean>

Source

Source • Demo • Docs