Detects user’s transparency preferences using the 'prefers-reduced-transparency' CSS3 level 5 media query.

Usage no npm install needed!

<script type="module">
  import magica11yPrefersReducedTransparency from 'https://cdn.skypack.dev/@magica11y/prefers-reduced-transparency';



Detects user’s transparency preferences using the prefers-reduced-transparency CSS3 level 5 media query.

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:sparkles: Introduction

Quoting from the CSS3 level 5 media queries specfication…

The '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, which provides a suite of functions to detect “user-preference” and “environment” media features.

Magica11y functions are awesome because…

  • They have zero dependencies
  • They’re lightweight; e.g. prefersReducedTransparency() is just Bundlephobia minified, or Bundlephobia minified & gzipp’d
  • They use the 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 also provides…

:rocket: Getting started

:building_construction: Installation

You can install prefersReducedTransparency() using a package manager such as yarn or npm

$ 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 or unpkg

<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 module, so you can use it as a browser global…

var transparencyPreference = window.magica11y.prefersReducedTransparency.default();
var reduceTransparency = (transparencyPreference === window.magica11y.prefersReducedTransparency.transparencyPreferences.DARK);

… or as a CommonJS module…

const prefersReducedTransparency = require('@magica11y/prefers-reduced-transparency');
const transparencyPreference = prefersReducedTransparency.default();
const reduceTransparency = (transparencyPreference === prefersReducedTransparency.transparencyPreferences.REDUCE);

… or as an ES module…

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')

    Indicates that the user has made no preference known to the system.

  • transparencyPreferences.REDUCE (spec: '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 types from the provided libdefs in node_modules/@magica11y/prefers-reduced-transparency/lib by configuring them in your .flowconfig


Now, you can use the Flow types as follows…

// @flow
import prefersReducedTransparency, { type TransparencyPreference } from '@magica11y/prefers-reduced-transparency';

const transparencyPreference: ?TransparencyPreference = prefersReducedTransparency();

:tophat: Note: prefersReducedTransparency() returns a nullable type (i.e. TransparencyPreference). So using the ? prefix to indicate nullable types is recommended (i.e. ?TransparencyPreference).

:scroll: License


See LICENSE.md for more details.

Handcrafted with :heart: by Rishabh.