npm package: @magica11y/prefers-color-scheme
Description: Detects user’s color scheme preferences using the 'prefers-color-scheme' CSS3 level 5 media query.
Author: Rishabh
Latest version: 2.0.3

`prefersColorScheme()`
======================
> Detects user’s color scheme preferences using the `prefers-color-scheme` CSS3 level 5 media query.

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# :sparkles: Introduction

Quoting from the [CSS3](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS3) [level 5](https://www.w3.org/TR/mediaqueries-5/)
[media queries](https://developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries) specfication…

> The [`'prefers-color-scheme'`](https://www.w3.org/TR/mediaqueries-5/#prefers-color-scheme) media feature reflects the user’s desire that the page use a light or dark color theme.

:high_brightness: **`prefersColorScheme()`** is part of :crystal_ball: [**Magica11y**](https://magica11y.github.io),
which provides a suite of functions to detect “user-preference” and “environment” media features.

[Magica11y](https://magica11y.github.io) functions are awesome because…
  * They have **zero** dependencies
  * They’re **lightweight**; e.g. `prefersColorScheme()` is just [![Bundlephobia](https://img.shields.io/bundlephobia/min/@magica11y/prefers-color-scheme.svg?style=flat-square&label "Bundle size (minified)")](https://bundlephobia.com/result?p=@magica11y/prefers-color-scheme) minified, or [![Bundlephobia](https://img.shields.io/bundlephobia/minzip/@magica11y/prefers-color-scheme.svg?style=flat-square&label "Bundle size (minified+gzipped)")](https://bundlephobia.com/result?p=@magica11y/prefers-color-scheme) minified & gzipp’d
  * They use the **[`window.matchMedia`](https://developer.mozilla.org/docs/Web/API/Window/matchMedia)** API underneath
  * They’re optimized for **performance**; all the module functions are designed in such a way that they exit early
  * They provide a **clean**, **well-documented** and **semantic** API to work with

In addition to `prefersColorScheme()`, [Magica11y](https://magica11y.github.io) also provides…

  * :tv: [`environmentBlending()`](https://github.com/magica11y/environment-blending)
  * :art: [`forcedColors()`](https://github.com/magica11y/forced-colors)
  * :new_moon: [`invertedColors()`](https://github.com/magica11y/inverted-colors)
  * ~:candle: [`lightLevel()`](https://github.com/magica11y/light-level)~
  * :high_brightness: [`prefersContrast()`](https://github.com/magica11y/prefers-contrast)
  * :roller_coaster: [`prefersReducedMotion()`](https://github.com/magica11y/prefers-reduced-motion)
  * :gem: [`prefersReducedTransparency()`](https://github.com/magica11y/prefers-reduced-transparency)

# :rocket: Getting started

## :building_construction: Installation

You can install `prefersColorScheme()` using a package manager such as [`yarn`](https://yarnpkg.com/en/package/@magica11y/prefers-color-scheme) or [`npm`](https://www.npmjs.com/package/@magica11y/prefers-color-scheme)…

```sh
$ yarn add "@magica11y/prefers-color-scheme"
# OR
$ npm install --save "@magica11y/prefers-color-scheme"
```

You can also include `prefersColorScheme()` from a CDN on your page, such as [jsDelivr](https://www.jsdelivr.com/package/npm/@magica11y/prefers-color-scheme) or [unpkg](https://unpkg.com/@magica11y/prefers-color-scheme)…

```html
<script src="https://cdn.jsdelivr.net/npm/@magica11y/prefers-color-scheme@latest/dist/magica11y.prefersColorScheme.min.js"></script>
<!-- OR -->
<script src="https://unpkg.com/@magica11y/prefers-color-scheme@latest/dist/magica11y.prefersColorScheme.js"></script>
```

## :game_die: Usage

`prefersColorScheme()` is distributed as a [UMD](https://github.com/umdjs/umd) module, so you can use it as a browser global…

```js
var preferredColorScheme = window.magica11y.prefersColorScheme.default();
var enableDarkTheme = (preferredColorScheme === window.magica11y.prefersColorScheme.colorSchemes.DARK);
```

… or as a CommonJS module…

```js
const prefersColorScheme = require('@magica11y/prefers-color-scheme');
const preferredColorScheme = prefersColorScheme.default();
const enableDarkTheme = (preferredColorScheme === prefersColorScheme.colorSchemes.DARK);
```

… or as an ES module…

```js
import prefersColorScheme, { colorSchemes } from '@magica11y/prefersColorScheme';

const preferredColorScheme = prefersColorScheme();
const enableDarkTheme = (preferredColorScheme === colorSchemes.DARK);
```

The `colorSchemes` object contains all the possible values supported by the `'prefers-color-scheme'` media query…

* `colorSchemes.LIGHT` (spec: [`'light'`](https://www.w3.org/TR/mediaqueries-5/#valdef-media-prefers-color-scheme-light))
  > Indicates that user has expressed the preference for a page that has a light theme (dark text on light background), or has not expressed an active preference (and thus should receive the "web default" of a light theme).
* `colorSchemes.DARK` (spec: [`'dark'`](https://www.w3.org/TR/mediaqueries-5/#valdef-media-prefers-color-scheme-dark))
  > Indicates that user has expressed the preference for a page that has a dark theme (light text on dark background).
* `null`
  > The user’s preference could not be determined.


# :checkered_flag: Typechecking

You can import the [Flow](https://flow.org) types from the provided [libdefs](https://flow.org/en/docs/libdefs)
in `node_modules/@magica11y/prefers-color-scheme/lib` by configuring them in your `.flowconfig`…

```
[libs]
node_modules/@magica11y/prefers-color-scheme/lib
```

Now, you can use the Flow types as follows…

```js
// @flow
import prefersColorScheme, { type ColorScheme } from '@magica11y/prefers-color-scheme';

const preferredColorScheme: ?ColorScheme = prefersColorScheme();
```

:tophat: **Note**: `prefersColorScheme()` returns a [`nullable`](https://flow.org/en/docs/types/primitives/#toc-null-and-void)
type (i.e. `ColorScheme`). So using the `?` prefix to indicate nullable types is recommended (i.e. `?ColorScheme`).


# :scroll: License

[![License](https://img.shields.io/github/license/magica11y/magica11y.svg?style=for-the-badge "MIT license")](LICENSE.md)

See [LICENSE.md](LICENSE.md) for more details.

Handcrafted with :heart: by [Rishabh](https://rishabh.ink).

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