react-a11y

React A11y
==========


Warns about potential accessibility issues with your React elements.

!screenshot

Installation

Run:

``bash
npm install react-a11y
`

Usage

In your main application file, require the module and call it, you'll start
getting warnings in the console as your app renders. Note that by default all
rules are turned off so you need to turn them on first (by setting them to
"warn" or "error").

`javascript
import React from 'react';
import ReactDOM from 'react-dom';

if (process.env.NODE_ENV === 'development') {
const a11y = require('react-a11y').default;
a11y(React, ReactDOM, {
rules: {
'img-uses-alt': 'warn',
'redundant-alt': [ 'warn', [ 'image', 'photo', 'foto', 'bild' ]]
// ...
}
});
}
`

You probably don't want to call it if you're in production, since it patches the
React rendering functions and this might make this slower.

Options

These are the supported configuration options, annotated using [flow][] type
annotations

`flow js
a11y(React : React, ReactDOM : ReactDOM, opts : object? );
`

React is the React object you want to shim to allow the
accessibility tests.

ReactDOM is the ReactDOM object you're using to render the
React components. This is only used on the client side, so you
can safely omit it when using react-a11y in node.

$3


- plugins : [string]
An array of strings corresponding to names of plugins to be used.
Eg. if the array contains 'aria-wai' it would include the rules
in a (yet to be written) react-a11y-plugin-aria-wai module. You
are responsible for installing this module.

- rules : object
The configuration options for each of the rules. This uses the same format
as [eslint][] does:

`javascript
const rules = {
'img-uses-alt': 'off',
'redundant-alt': [
'warn',
// other options to pass to the rule:
[
'foto'
]
]
};
`

Refer to the rule docs
to see what options are defined for each rule.

- reporter : object => undefined
Use this to modify how the warnings are displayed.
The reporter is a function that accepts an object with
the following keys:
- msg : string - the error message
- tagName : string - the tagName of the violating element (eg. 'img')
- severity : string - the severity as configured by the user in the
corresponding rule configuration (one of 'off', 'warn', or 'error')
- props : object - the props as passed to the element
- displayName : string? - the displayName of the owner, if any
- DOMNode : object? - the violating DOMNode as rendered to the browser
DOM, this is only available on when react-a11y is running in the
browser.
- url : string? - The url to a webpage explaining why this rule
is important

The default reporter displays all the information it can, but listens
to the deprecated options includeSrcNode, warningPrefix and
throwErro and throwError.

- filterFn : (string, string, string) => boolean
You can filter failures by passing a function to the filterFn option. The
filter function will receive three arguments: the name of the Component
instance or ReactElement, the id of the violating element, and the failure
message.

Note: If it is a ReactElement, the name will be the node type (eg. div)

`javascript
// only show errors on CommentList
const commentListFailures = function (name, id, msg) {
return name === "CommentList";
};

a11y(React, ReactDOM, { filterFn: commentListFailures });
`

Cleaning Up In Tests

Use the restoreAll() method to clean up mutations made to React.
Useful if you are using react-a11y in your test suite:

`javascript
beforeEach(() => a11y(React));
afterEach(() => a11y.restoreAll());
`

Writing plugins

The rules in this version of react-a11y` are pluggable!
You can write your own plugin to add more rules. Have a look at
writing plugins in the
docs to get started!

Contributing

Interested in contributing? Great! Look here for more info: CONTRIBUTING.md.

[react-a11y]: https://github.com/reactjs/react-a11y
[eslint]: http://eslint.org
[flow]: http://flowtype.org
[eslint-plugin]: https://github.com/evcohen/eslint-plugin-jsx-a11y
[AX]: https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules