@magica11y/prefers-reduced-transparency
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Detects user’s transparency preferences using the 'prefers-reduced-transparency' CSS3 level 5 media query.
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`prefersReducedTransparency()`
==============================
> Detects user’s transparency preferences using the `prefers-reduced-transparency` CSS3 level 5 media query.
[](https://travis-ci.com/magica11y/prefers-reduced-transparency)
[](https://www.npmjs.com/package/@magica11y/prefers-reduced-transparency)
[](https://bundlephobia.com/result?p=@magica11y/prefers-reduced-transparency)
[](https://bundlephobia.com/result?p=@magica11y/prefers-reduced-transparency)
[](https://coveralls.io/github/magica11y/prefers-reduced-transparency)
[](https://david-dm.org/magica11y/prefers-reduced-transparency)
[](https://david-dm.org/magica11y/prefers-reduced-transparency?type=dev)
[](https://www.npmjs.com/package/@magica11y/prefers-reduced-transparency)
[](LICENSE.md)
[](https://snyk.io/test/github/magica11y/prefers-reduced-transparency?targetFile=package.json)
[](https://magica11y.github.io)
# :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-reduced-transparency'`](https://www.w3.org/TR/mediaqueries-5/#prefers-reduced-transparency) media feature
> is used to detect if the user has requested the system minimize the amount of transparent or translucent layer effects it uses.
:high_brightness: **`prefersReducedTransparency()`** 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. `prefersReducedTransparency()` is just [](https://bundlephobia.com/result?p=@magica11y/prefers-reduced-transparency) minified, or [](https://bundlephobia.com/result?p=@magica11y/prefers-reduced-transparency) 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 `prefersReducedTransparency()`, [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)
* :last_quarter_moon: [`prefersColorScheme()`](https://github.com/magica11y/prefers-color-scheme)
# :rocket: Getting started
## :building_construction: Installation
You can install `prefersReducedTransparency()` using a package manager such as [`yarn`](https://yarnpkg.com/en/package/@magica11y/prefers-reduced-transparency) or [`npm`](https://www.npmjs.com/package/@magica11y/prefers-reduced-transparency)…
```sh
$ yarn add "@magica11y/prefers-reduced-transparency"
# OR
$ npm install --save "@magica11y/prefers-reduced-transparency"
```
You can also include `prefersReducedTransparency()` from a CDN on your page, such as [jsDelivr](https://www.jsdelivr.com/package/npm/@magica11y/prefers-reduced-transparency) or [unpkg](https://unpkg.com/@magica11y/prefers-reduced-transparency)…
```html
<script src="https://cdn.jsdelivr.net/npm/@magica11y/prefers-reduced-transparency@latest/dist/magica11y.prefersReducedTransparency.min.js"></script>
<!-- OR -->
<script src="https://unpkg.com/@magica11y/prefers-reduced-transparency@latest/dist/magica11y.prefersReducedTransparency.js"></script>
```
## :game_die: Usage
`prefersReducedTransparency()` is distributed as a [UMD](https://github.com/umdjs/umd) module, so you can use it as a browser global…
```js
var transparencyPreference = window.magica11y.prefersReducedTransparency.default();
var reduceTransparency = (transparencyPreference === window.magica11y.prefersReducedTransparency.transparencyPreferences.DARK);
```
… or as a CommonJS module…
```js
const prefersReducedTransparency = require('@magica11y/prefers-reduced-transparency');
const transparencyPreference = prefersReducedTransparency.default();
const reduceTransparency = (transparencyPreference === prefersReducedTransparency.transparencyPreferences.REDUCE);
```
… or as an ES module…
```js
import prefersReducedTransparency, { transparencyPreferences } from '@magica11y/prefersReducedTransparency';
const transparencyPreference = prefersReducedTransparency();
const reduceTransparency = (transparencyPreference === transparencyPreferences.REDUCE);
```
The `transparencyPreferences` object contains all the possible values supported by the `'prefers-reduced-transparency'` media query…
* `transparencyPreferences.NO_PREFERENCE` (spec: [`'no-preference'`](https://www.w3.org/TR/mediaqueries-5/#valdef-media-prefers-reduced-transparency-no-preference))
> Indicates that the user has made no preference known to the system.
* `transparencyPreferences.REDUCE` (spec: [`'reduce'`](https://www.w3.org/TR/mediaqueries-5/#valdef-media-prefers-reduced-transparency-reduce))
> Indicates that user has notified the system that they prefer an interface that minimizes the amount of transparent or translucent layer effects.
* `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-reduced-transparency/lib` by configuring them in your `.flowconfig`…
```
[libs]
node_modules/@magica11y/prefers-reduced-transparency/lib
```
Now, you can use the Flow types as follows…
```js
// @flow
import prefersReducedTransparency, { type TransparencyPreference } from '@magica11y/prefers-reduced-transparency';
const transparencyPreference: ?TransparencyPreference = prefersReducedTransparency();
```
:tophat: **Note**: `prefersReducedTransparency()` returns a [`nullable`](https://flow.org/en/docs/types/primitives/#toc-null-and-void)
type (i.e. `TransparencyPreference`). So using the `?` prefix to indicate nullable types is recommended (i.e. `?TransparencyPreference`).
# :scroll: License
[](LICENSE.md)
See [LICENSE.md](LICENSE.md) for more details.
Handcrafted with :heart: by [Rishabh](https://rishabh.ink).
[](https://twitter.com/rishabh_ink)