trendingtechnology / react-a11y

Identifies accessibility issues in your React.js elements

React A11y

Warns about potential accessibility issues with your React elements.

Installation

Run:

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").

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

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.

options:

• 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:

  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)

  // 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:

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.