@magica11y/prefers-reduced-motion NPM

`prefersReducedMotion()`

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

:sparkles: Introduction

Quoting from the CSS3 level 5 media queries specfication…

The prefers-reduced-motion media feature is used to detect if the user has requested the system to minimize the amount of animation or motion it uses.

:roller_coaster: prefersReducedMotion() 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. prefersReducedMotion() is just minified, or 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 prefersReducedMotion(), Magica11y also provides…

:tv: environmentBlending()
:art: forcedColors()
:new_moon: invertedColors()
~:candle: lightLevel()~
:last_quarter_moon: prefersColorScheme()
:high_brightness: prefersContrast()
:gem: prefersReducedTransparency()

:rocket: Getting started

:building_construction: Installation

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

$ yarn add "@magica11y/prefers-reduced-motion"
# OR
$ npm install --save "@magica11y/prefers-reduced-motion"

You can also include prefersReducedMotion() from a CDN on your page, such as jsDelivr or unpkg…

<script src="https://cdn.jsdelivr.net/npm/@magica11y/prefers-reduced-motion@latest/dist/magica11y.prefersReducedMotion.min.js"></script>
<!-- OR -->
<script src="https://unpkg.com/@magica11y/prefers-reduced-motion@latest/dist/magica11y.prefersReducedMotion.js"></script>

:game_die: Usage

prefersReducedMotion() is distributed as a UMD module, so you can use it as a browser global…

var motionPreference = window.magica11y.prefersReducedMotion.default();
var disableAnimations = (motionPreference === window.magica11y.prefersReducedMotion.motionPreferences.REDUCE);

… or as a CommonJS module…

const prefersReducedMotion = require('@magica11y/prefers-reduced-motion');
const motionPreference = prefersReducedMotion.default();
const disableAnimations = (motionPreference === prefersReducedMotion.motionPreferences.REDUCE);

… or as an ES module…

import prefersReducedMotion, { motionPreferences } from '@magica11y/prefers-reduced-motion';

const motionPreference = prefersReducedMotion();
const disableAnimations = (motionPreference === motionPreferences.REDUCE);

The motionPreferences object contains all the possible values supported by the 'prefers-reduce-motion' media query…

motionPreferences.NO_PREFERENCE (spec: 'no-preference')
Indicates that the user has made no preference known to the system.
motionPreferences.REDUCE (spec: 'reduce')
Indicates that user has notified the system that they prefer an interface that minimizes the amount of movement or animation, preferably to the point where all non-essential movement is removed.
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-motion/lib by configuring them in your .flowconfig…

[libs]
node_modules/@magica11y/prefers-reduced-motion/lib

Now, you can use the Flow types as follows…

// @flow
import prefersReducedMotion, { type MotionPreference } from '@magica11y/prefers-reduced-motion';

const motionPreference: ?MotionPreference = prefersReducedMotion();

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