lighthouse/core/audits/accessibility/input-image-alt.js

Automated auditing, performance metrics, and best practices for the web.

/**
 * @license
 * Copyright 2017 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Ensures `<input type="image">` elements have alternate text.
 * See base class in axe-audit.js for audit() implementation.
 */

import AxeAudit from './axe-audit.js';
import * as i18n from '../../lib/i18n/i18n.js';

const UIStrings = {
  /** Title of an accesibility audit that evaluates if all input elements of type image have an alt HTML attribute to describe their contents. This title is descriptive of the successful state and is shown to users when no user action is required. */
  title: '`<input type="image">` elements have `[alt]` text',
  /** Title of an accesibility audit that evaluates if all input elements of type image have an alt HTML attribute to describe their contents. This title is descriptive of the failing state and is shown to users when there is a failure that needs to be addressed. */
  failureTitle: '`<input type="image">` elements do not have `[alt]` text',
  /** Description of a Lighthouse audit that tells the user *why* they should try to pass. This is displayed after a user expands the section to see more. No character length limits. The last sentence starting with 'Learn' becomes link text to additional documentation. */
  description: 'When an image is being used as an `<input>` button, providing alternative ' +
      'text can help screen reader users understand the purpose of the button. ' +
      '[Learn about input image alt text](https://dequeuniversity.com/rules/axe/4.10/input-image-alt).',
};

const str_ = i18n.createIcuMessageFn(import.meta.url, UIStrings);

class InputImageAlt extends AxeAudit {
  /**
   * @return {LH.Audit.Meta}
   */
  static get meta() {
    return {
      id: 'input-image-alt',
      title: str_(UIStrings.title),
      failureTitle: str_(UIStrings.failureTitle),
      description: str_(UIStrings.description),
      requiredArtifacts: ['Accessibility'],
    };
  }
}

export default InputImageAlt;
export {UIStrings};