What is eslint-plugin-jsx-a11y?
The eslint-plugin-jsx-a11y npm package is a collection of accessibility-related rules for ESLint that enforce best practices for accessibility in JSX (most commonly used with React). It helps developers write code that is accessible to users with disabilities by checking for common accessibility errors and suggesting improvements.
What are eslint-plugin-jsx-a11y's main functionalities?
Accessible elements
Ensures interactive elements are accessible. For example, this rule checks that buttons have an accessible name and can be interacted with via keyboard.
<button onClick={this.handleClick}>Click me</button>
Aria roles
Enforces the use of valid ARIA roles and that elements with ARIA roles have the required attributes for that role.
<div role="button" onClick={this.handleRoleClick}>Role Button</div>
Media captions
Ensures media elements such as audio and video have captions or descriptions to aid users who cannot see or hear the content.
<video><track kind="captions" /></video>
No redundant alt text
Prevents the use of redundant alt text in images, which can be frustrating for screen reader users.
<img src="image.jpg" alt="" />
Keyboard accessibility
Ensures that custom interactive elements are focusable and have keyboard event handlers to mimic native interactive elements.
<div tabIndex="0" onKeyDown={this.handleKeyDown}>Focusable Div</div>
Other packages similar to eslint-plugin-jsx-a11y
eslint-plugin-vuejs-accessibility
Similar to eslint-plugin-jsx-a11y, but specifically tailored for Vue.js applications. It provides a set of accessibility rules for Vue.js templates.
eslint-plugin-react
While not exclusively focused on accessibility, eslint-plugin-react includes some rules related to accessibility. It is a broader linting tool for React-specific code practices.
axe-core
Although not an ESLint plugin, axe-core is a library for accessibility testing that can be integrated into testing frameworks. It provides comprehensive accessibility checks that can be run on rendered HTML, complementing the static analysis provided by eslint-plugin-jsx-a11y.
eslint-plugin-jsx-a11y
Static AST checker for accessibility rules on JSX elements.
Why?
Ryan Florence built out this awesome runtime-analysis tool called react-a11y. It is super useful. However, since you're probably already using linting in your project, this plugin comes for free and closer to the actual development process. Pairing this plugin with an editor lint plugin, you can bake accessibility standards into your application in real-time.
Note: This project does not replace react-a11y, but can and should be used in conjunction with it. Static analysis tools cannot determine values of variables that are being placed in props before runtime, so linting will not fail if that value is undefined and/or does not pass the lint rule.
Installation
You'll first need to install ESLint:
$ npm i eslint --save-dev
Next, install eslint-plugin-jsx-a11y
:
$ npm install eslint-plugin-jsx-a11y --save-dev
Note: If you installed ESLint globally (using the -g
flag) then you must also install eslint-plugin-jsx-a11y
globally.
Usage
Add jsx-a11y
to the plugins section of your .eslintrc
configuration file. You can omit the eslint-plugin-
prefix:
{
"plugins": [
"jsx-a11y"
]
}
Then configure the rules you want to use under the rules section.
{
"rules": {
"jsx-a11y/rule-name": 2
}
}
Supported Rules
- aria-props: Enforce all
aria-*
props are valid. - aria-proptypes: Enforce ARIA state and property values are valid.
- aria-role: Enforce that elements with ARIA roles must use a valid, non-abstract ARIA role.
- aria-unsupported-elements: Enforce that elements that do not support ARIA roles, states, and properties do not have those attributes.
- heading-has-content: Enforce heading (
h1
, h2
, etc) elements contain accessible content. - href-no-hash: Enforce an anchor element's
href
prop value is not just #
. - html-has-lang: Enforce
<html>
element has lang
prop. - img-has-alt: Enforce that
<img>
JSX elements use the alt
prop. - img-redundant-alt: Enforce
<img>
alt prop does not contain the word "image", "picture", or "photo". - label-has-for: Enforce that
<label>
elements have the htmlFor
prop. - lang: Enforce lang attribute has a valid value.
- mouse-events-have-key-events: Enforce that
onMouseOver
/onMouseOut
are accompanied by onFocus
/onBlur
for keyboard-only users. - no-access-key: Enforce that the
accessKey
prop is not used on any element to avoid complications with keyboard commands used by a screenreader. - no-marquee: Enforce
<marquee>
elements are not used. - no-onchange: Enforce that
onBlur
is used instead of onChange
. - onclick-has-focus: Enforce that elements with
onClick
handlers must be focusable. - onclick-has-role: Enforce that non-interactive, visible elements (such as
<div>
) that have click handlers use the role attribute. - role-has-required-aria-props: Enforce that elements with ARIA roles must have all required attributes for that role.
- role-supports-aria-props: Enforce that elements with explicit or implicit roles defined contain only
aria-*
properties supported by that role
. - scope: Enforce
scope
prop is only used on <th>
elements. - tabindex-no-positive: Enforce
tabIndex
value is not greater than zero.
License
eslint-plugin-jsx-a11y is licensed under the MIT License.