/**
* @license
* Copyright 2016 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
const Audit = require('../audit');
const Formatter = require('../../../formatters/formatter');
class ImageAlt extends Audit {
/**
* @override
*/
static get meta() {
return {
category: 'Accessibility',
name: 'image-alt',
description: 'Every image element has an alt attribute',
requiredArtifacts: ['accessibility']
};
}
/**
* @param {!Artifacts} artifacts
* @return {!AuditResult}
*/
static audit(artifacts) {
const rule =
artifacts.accessibility.violations.find(result => result.id === 'image-alt');
return ImageAlt.generateAuditResult({
value: typeof rule === 'undefined',
debugString: this.createDebugString(rule),
extendedInfo: {
formatter: Formatter.SUPPORTED_FORMATS.ACCESSIBILITY,
value: rule
}
});
}
static createDebugString(rule) {
if (typeof rule === 'undefined') {
return '';
}
const elementsStr = rule.nodes.length === 1 ? 'element' : 'elements';
return `${rule.help} (Failed on ${rule.nodes.length} ${elementsStr})`;
}
}
module.exports = ImageAlt;
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