lighthouse/core/computed/page-dependency-graph.js

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

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

import * as Lantern from '../lib/lantern/lantern.js';
import {makeComputedArtifact} from './computed-artifact.js';
import {NetworkRequest} from '../lib/network-request.js';
import {ProcessedTrace} from './processed-trace.js';
import {NetworkRecords} from './network-records.js';
import {TraceEngineResult} from './trace-engine-result.js';

class PageDependencyGraph {
  /**
   * @param {{trace: LH.Trace, devtoolsLog: LH.DevtoolsLog, settings: LH.Audit.Context['settings'], URL: LH.Artifacts['URL'], SourceMaps: LH.Artifacts['SourceMaps'], fromTrace: boolean}} data
   * @param {LH.Artifacts.ComputedContext} context
   * @return {Promise<LH.Gatherer.Simulation.GraphNode>}
   */
  static async compute_(data, context) {
    const {trace, settings, devtoolsLog, URL, SourceMaps} = data;
    const [{mainThreadEvents}, networkRecords] = await Promise.all([
      ProcessedTrace.request(trace, context),
      NetworkRecords.request(devtoolsLog, context),
    ]);

    if (data.fromTrace) {
      const traceEngineResult =
        await TraceEngineResult.request({trace, settings, SourceMaps}, context);
      const parsedTrace = traceEngineResult.parsedTrace;
      const requests =
        Lantern.TraceEngineComputationData.createNetworkRequests(trace, parsedTrace);
      const graph =
        Lantern.TraceEngineComputationData.createGraph(requests, trace, parsedTrace, URL);
      // @ts-expect-error for now, ignore that this is a SyntheticNetworkEvent instead of LH's NetworkEvent.
      return graph;
    }

    // TODO: currently the trace version has no requests that failed, or requests that have "Preflight".
    //       so the following gets the devtools log version _closer_ to the exact same results as the trace.
    // const lanternRequests = networkRecords.map(NetworkRequest.asLanternNetworkRequest).filter(r => !r.failed && r.resourceType !== 'Preflight');

    const lanternRequests = networkRecords.map(NetworkRequest.asLanternNetworkRequest);
    return Lantern.Graph.PageDependencyGraph.createGraph(mainThreadEvents, lanternRequests, URL);
  }
}

const PageDependencyGraphComputed = makeComputedArtifact(PageDependencyGraph,
  ['devtoolsLog', 'settings', 'trace', 'URL', 'SourceMaps', 'fromTrace']);
export {PageDependencyGraphComputed as PageDependencyGraph};