core/audits/resource-summary.js

/**
 * @license Copyright 2019 The Lighthouse Authors. 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 https://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.
 */

import {Audit} from './audit.js';
import {ResourceSummary as ComputedResourceSummary} from '../computed/resource-summary.js';
import * as i18n from '../lib/i18n/i18n.js';

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

/** @typedef {import('../computed/resource-summary.js').ResourceType} ResourceType */

class ResourceSummary extends Audit {
  /**
   * @return {LH.Audit.Meta}
   */
  static get meta() {
    return {
      id: 'resource-summary',
      title: 'Resources Summary',
      description: 'Aggregates all network requests and groups them by type',
      scoreDisplayMode: Audit.SCORING_MODES.INFORMATIVE,
      requiredArtifacts: ['DevtoolsLog', 'URL'],
    };
  }

  /**
   * @param {LH.Artifacts} artifacts
   * @param {LH.Audit.Context} context
   * @return {Promise<LH.Audit.Product>}
   */
  static async audit(artifacts, context) {
    const devtoolsLog = artifacts.DevtoolsLog;
    const summary = await ComputedResourceSummary
      .request({devtoolsLog, URL: artifacts.URL}, context);

    /** @type {LH.Audit.Details.Table['headings']} */
    const headings = [
      {key: 'label', valueType: 'text', label: str_(i18n.UIStrings.columnResourceType)},
      {key: 'requestCount', valueType: 'numeric', label: str_(i18n.UIStrings.columnRequests)},
      {key: 'transferSize', valueType: 'bytes', label: str_(i18n.UIStrings.columnTransferSize)},
    ];

    /** @type {Record<ResourceType, LH.IcuMessage>} */
    const strMappings = {
      'total': str_(i18n.UIStrings.totalResourceType),
      'document': str_(i18n.UIStrings.documentResourceType),
      'script': str_(i18n.UIStrings.scriptResourceType),
      'stylesheet': str_(i18n.UIStrings.stylesheetResourceType),
      'image': str_(i18n.UIStrings.imageResourceType),
      'media': str_(i18n.UIStrings.mediaResourceType),
      'font': str_(i18n.UIStrings.fontResourceType),
      'other': str_(i18n.UIStrings.otherResourceType),
      'third-party': str_(i18n.UIStrings.thirdPartyResourceType),
    };

    const types = /** @type {Array<ResourceType>} */ (Object.keys(summary));
    const rows = types.map(type => {
      return {
        // ResourceType is included as an "id" for ease of use.
        // It does not appear directly in the table.
        resourceType: type,
        label: strMappings[type],
        requestCount: summary[type].count,
        transferSize: summary[type].transferSize,
      };
    });
    // Force third-party to be last, descending by size otherwise
    const thirdPartyRow = rows.find(r => r.resourceType === 'third-party') || [];
    const otherRows = rows.filter(r => r.resourceType !== 'third-party')
      .sort((a, b) => {
        return b.transferSize - a.transferSize;
      });
    const tableItems = otherRows.concat(thirdPartyRow);

    const tableDetails = Audit.makeTableDetails(headings, tableItems);

    return {
      details: tableDetails,
      score: null,
    };
  }
}

export default ResourceSummary;