/vueuse-functions

useDark

Reactive dark mode with auto data persistence.

<CourseLink href="https://vueschool.io/lessons/theming-with-vueuse-usedark-and-usecolormode?friend=vueuse">Learn useDark with this FREE video lesson from Vue School!</CourseLink>

Basic Usage

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

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

Behavior

useDark combines with usePreferredDark and useStorage. On start up, it reads the value from localStorage/sessionStorage (the key is configurable) to see if there is a 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 (default key: vueuse-color-scheme) for persistence.

Please note useDark only 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>

Still, you can also customize it to make it work with most CSS frameworks.

For example:

import { useDark } from '@vueuse/core'
// ---cut---
const isDark = useDark({
  selector: 'body',
  attribute: 'color-scheme',
  valueDark: 'dark',
  valueLight: 'light',
})

will work like

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

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

If the configuration above still does not fit your needs, you can use theonChanged option to take full control over how you handle updates.

import { useDark } from '@vueuse/core'
// ---cut---
const isDark = useDark({
  onChanged(dark) {
    // update the dom, call the API or something
  },
})

Component Usage

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

Type Declarations

export interface UseDarkOptions extends Omit<
  UseColorModeOptions<BasicColorSchema>,
  "modes" | "onChanged"
> {
  /**
   * 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 overridden.
   *
   * @default undefined
   */
  onChanged?: (
    isDark: boolean,
    defaultHandler: (mode: BasicColorSchema) => void,
    mode: BasicColorSchema,
  ) => void
}
export type UseDarkReturn = WritableComputedRef<boolean>
/**
 * Reactive dark mode with auto data persistence.
 *
 * @see https://vueuse.org/useDark
 * @param options
 */
export declare function useDark(options?: UseDarkOptions): UseDarkReturn