Lighthouse CI Get Diffs For Hashes (DISCLAIMER: untested)

find-diffs.js

const ApiClient = require('@lhci/utils/src/api-client')
const {findAuditDiffs} = require('@lhci/utils/src/audit-diff-finder')
const client = new ApiClient({rootURL: 'http://lhci-server.example.com'})

const PROJECT_ID = '<UUID of project>'

async function getLHR(hash, url) {
  const [build] = await client.getBuilds(PROJECT_ID, {hash})  
  const [run] = await client.getRuns(PROJECT_ID, build.id, {representative: true, url})
  return JSON.parse(run.lhr)
}

async function findDiffs(hashA, hashB, url) {
  const lhrA = await getLHR(hashA, url)
  const lhrB = await getLHR(hashB, url)

  const diffs = []
  for (const auditId of Object.keys(lhrA.audits)) {
    diffs.push(findAuditDiffs(lhrA.audits[auditId], lhrB.audits[auditId]))
  }

  return diffs
}

I think this is pretty close to done now, the results out of this is a pretty good list of entries that have been impacted, and we only show entries with numericValue type. Maybe we can add a list of audits that are 'key' to give feedback, such as first-cpu-idle as extra options for the findDiffs function 🤔, cause even filtering out a lot of the entries by narrowing down to numericValue ones only, we still have quite a number of entries 😁.

const ApiClient = require('@lhci/utils/src/api-client');
const { findAuditDiffs } = require('@lhci/utils/src/audit-diff-finder');
const {
  ci: {
    upload: { serverBaseUrl: rootURL, token },
  },
} = require('path to project lighthouserc.json');

const client = new ApiClient({ rootURL });

async function findProjectID(projectToken = token) {
  return await client.findProjectByToken(projectToken);
}

async function getLHR(hash, projectId) {
  const [build] = await client.getBuilds(projectId, { hash });
  const [run] = await client.getRuns(projectId, build.id, {
    representative: true,
  });
  return JSON.parse(run.lhr);
}

async function findDiffs(hashA, hashB, projectId) {
  const lhrA = await getLHR(hashA, projectId);
  const lhrB = await getLHR(hashB, projectId);

  const diffs = [];
  for (const auditId of Object.keys(lhrA.audits)) {
    // remove empty diffs
    const diff = findAuditDiffs(lhrA.audits[auditId], lhrB.audits[auditId]);

    if (diff.length) {
      // filter diff to only include entries with 'numericValue' so we can better determine impact
      // also, flatten out the array
      diffs.push(...diff.filter(({type}) => type === 'numericValue'));
    }
  }

  return diffs;
}

/* example usage, so far
findProjectID().then(({ id }) => {
  findDiffs(
    'HASH1',
    'HASH2,
    id,
  ).then(console.log);
});
*/