byte-efficiency.js

/**
 * @license Copyright 2017 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 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.
 */

/**
 * @type {LH.Config}
 * Config file for running byte efficiency smokehouse audits.
 */
const config = {
  extends: 'lighthouse:default',
  settings: {
    onlyAudits: [
      'accesskeys', // run axe on the page since we've had problems with interactions
      'network-requests',
      'offscreen-images',
      'uses-http2',
      'modern-image-formats',
      'uses-optimized-images',
      'uses-text-compression',
      'uses-responsive-images',
      'unminified-css',
      'unminified-javascript',
      'unused-css-rules',
      'unused-javascript',
      // image-size-responsive is not a byte-efficiency audit but a counterbalance to the byte-efficiency audits
      // that makes sense to test together.
      'image-size-responsive',
      // unsized-images is not a byte-efficiency audit but can easily leverage the variety of images present in
      // byte-efficiency tests & thus makes sense to test together.
      'unsized-images',
      'script-elements-test-audit',
    ],
    throttlingMethod: 'devtools',
  },
  audits: [
    'unsized-images',
    {path: 'byte-efficiency/unused-javascript', options: {
      // Lower the threshold so we don't need huge resources to make a test.
      unusedThreshold: 2000,
    }},
    'script-elements-test-audit',
  ],
};

/**
 * @type {Smokehouse.ExpectedRunnerResult}
 * Expected Lighthouse results for byte efficiency audits.
 */
const expectations = {
  artifacts: {
    ScriptElements: [
      {
        type: null,
        src: null,
        async: false,
        defer: false,
        source: 'head',
        // Only do a single assertion for `devtoolsNodePath`: this can be flaky for elements
        // deep in the DOM, and the sample LHR test has plenty of places that would catch
        // a regression in `devtoolsNodePath` calculation. Keep just one for the benefit
        // of other smoke test runners.
        node: {
          devtoolsNodePath: '2,HTML,0,HEAD,3,SCRIPT',
        },
      },
      {
        type: 'application/javascript',
        src: 'http://localhost:10200/byte-efficiency/script.js',
        async: false,
        defer: false,
        source: 'head',
      },
      {
        type: null,
        src: 'http://localhost:10200/byte-efficiency/bundle.js',
        async: false,
        defer: false,
        source: 'head',
      },
      {
        type: null,
        src: null,
        async: false,
        defer: false,
        source: 'body',
      },
      {
        type: null,
        src: null,
        async: false,
        defer: false,
        source: 'body',
      },
      {
        type: null,
        src: null,
        async: false,
        defer: false,
        source: 'body',
      },
      {
        type: null,
        src: null,
        async: false,
        defer: false,
        source: 'body',
      },
      {
        type: null,
        src: 'http://localhost:10200/byte-efficiency/delay-complete.js?delay=8000',
        async: true,
        defer: false,
        source: 'body',
      },
    ],
    Scripts: {
      _includes: [
        {
          url: 'http://localhost:10200/byte-efficiency/tester.html',
          content: /generateInlineStyleWithSize/,
        },
        {
          url: 'http://localhost:10200/byte-efficiency/tester.html',
          content: /image-in-shadow-root/,
        },
        {
          url: 'http://localhost:10200/byte-efficiency/tester.html',
          content: /definitely-unused/,
        },
        {
          url: 'http://localhost:10200/byte-efficiency/tester.html',
          content: /Used block #1/,
        },
        {
          name: '/some-custom-url.js',
          url: 'http://localhost:10200/byte-efficiency/tester.html',
          content: /Unused block #1/,
        },
        {
          url: 'http://localhost:10200/byte-efficiency/script.js',
        },
        {
          url: 'http://localhost:10200/byte-efficiency/bundle.js',
        },
        // This _does not_ appear because it's a fake
        // resource (so the response is not served as JS content type).
        // {
        //   url: 'http://localhost:10200/byte-efficiency/delay-complete.js?delay=8000',
        // },
      ],
      // Ensure the above is exhaustive (except for favicon, which won't be fetched in devtools/LR).
      _excludes: [
        {url: /^((?!favicon).)*$/s},
      ],
    },
  },
  lhr: {
    requestedUrl: 'http://localhost:10200/byte-efficiency/tester.html',
    finalDisplayedUrl: 'http://localhost:10200/byte-efficiency/tester.html',
    audits: {
      'uses-http2': {
        score: 1,
        details: {
          items: {
            // localhost gets a free pass on uses-h2
            length: 0,
          },
        },
      },
      'unminified-css': {
        details: {
          overallSavingsBytes: '>17000',
          items: {
            length: 2,
          },
        },
      },
      'unminified-javascript': {
        score: '<1',
        details: {
          // the specific ms value is not meaningful for this smoketest
          // *some largish amount* of savings should be reported
          overallSavingsMs: '>500',
          overallSavingsBytes: '>45000',
          items: [
            {
              url: 'http://localhost:10200/byte-efficiency/script.js',
              wastedBytes: '46555 +/- 100',
              wastedPercent: '87 +/- 5',
            },
            {
              // /some-custom-url.js,
              url: 'inline: \n  function unusedFunction() {\n    // U…',
              wastedBytes: '6690 +/- 100',
              wastedPercent: '99.6 +/- 0.1',
            },
            {
              url: 'inline: \n  // Used block #1\n  // FILLER DATA JU…',
              wastedBytes: '6569 +/- 100',
              wastedPercent: 100,
            },
            {
              url: 'http://localhost:10200/byte-efficiency/bundle.js',
              totalBytes: '12962 +/- 1000',
              wastedBytes: '2349 +/- 100',
              wastedPercent: '19 +/- 5',
            },
          ],
        },
      },
      'unused-css-rules': {
        details: {
          overallSavingsBytes: '>40000',
          items: {
            length: 2,
          },
        },
      },
      'unused-javascript': {
        score: '<1',
        details: {
          // the specific ms value here is not meaningful for this smoketest
          // *some* savings should be reported
          overallSavingsMs: '>0',
          overallSavingsBytes: '35000 +/- 1000',
          items: [
            {
              url: 'http://localhost:10200/byte-efficiency/script.js',
              totalBytes: '53000 +/- 1000',
              wastedBytes: '22000 +/- 1000',
            },
            {
              // /some-custom-url.js,
              url: 'http://localhost:10200/byte-efficiency/tester.html',
              totalBytes: '6700 +/- 500',
              wastedBytes: '6600 +/- 500',
            },
            {
              url: 'http://localhost:10200/byte-efficiency/bundle.js',
              totalBytes: '12913 +/- 1000',
              wastedBytes: '5827 +/- 200',
              subItems: {
                items: [
                  {source: '…./b.js', sourceBytes: '4417 +/- 50', sourceWastedBytes: '2191 +/- 50'},
                  {source: '…./c.js', sourceBytes: '2200 +/- 50', sourceWastedBytes: '2182 +/- 50'},
                  {source: '…webpack/bootstrap', sourceBytes: '2809 +/- 50', sourceWastedBytes: '1259 +/- 50'},
                ],
              },
            },
          ],
        },
      },
      'offscreen-images': {
        details: {
          items: [
            {
              url: /lighthouse-unoptimized.jpg$/,
            }, {
              url: /lighthouse-480x320.webp$/,
            }, {
              url: /lighthouse-480x320.webp\?invisible$/,
            }, {
              url: /large.svg$/,
            },
          ],
        },
      },
      'modern-image-formats': {
        details: {
          overallSavingsBytes: '137000 +/- 10000',
          items: [
            {url: /lighthouse-1024x680.jpg$/},
            {url: /lighthouse-unoptimized.jpg$/},
            {url: /lighthouse-480x320.jpg$/},
            {url: /lighthouse-480x320.jpg\?attributesized/},
            {url: /lighthouse-480x320.jpg\?css/},
            {url: /lighthouse-480x320.jpg\?sprite/},
          ],
        },
      },
      'uses-text-compression': {
        score: '<1',
        details: {
          // the specific ms value is not meaningful for this smoketest
          // *some largish amount* of savings should be reported
          overallSavingsMs: '>700',
          overallSavingsBytes: '>50000',
          items: {
            length: 3,
          },
        },
      },
      'uses-optimized-images': {
        details: {
          overallSavingsBytes: '>10000',
          items: {
            length: 1,
          },
        },
      },
      // Check that images aren't TOO BIG.
      'uses-responsive-images': {
        details: {
          overallSavingsBytes: '169000 +/- 5000',
          items: [
            {wastedPercent: '81 +/- 5', url: /lighthouse-1024x680.jpg/},
            {wastedPercent: '88 +/- 5', url: /lighthouse-2048x1356.webp\?size0/},
            {wastedPercent: '65 +/- 5', url: /lighthouse-480x320.jpg/},
            {wastedPercent: '65 +/- 5', url: /lighthouse-480x320\.jpg\?attributesized/},
            {wastedPercent: '81 +/- 5', url: /lighthouse-480x320.webp/},
          ],
        },
      },
      // Checks that images aren't TOO SMALL.
      'image-size-responsive': {
        details: {
          items: [
            // One of these is the ?duplicate variant and another is the
            // ?cssauto variant but sort order isn't guaranteed
            // since the pixel diff is equivalent for identical images.
            {url: /lighthouse-320x212-poor.jpg/},
            {url: /lighthouse-320x212-poor.jpg/},
            {url: /lighthouse-320x212-poor.jpg/},
          ],
        },
      },
      'unsized-images': {
        details: {
          items: [
            {url: /lighthouse-320x212-poor\.jpg/},
            {url: /lighthouse-320x212-poor\.jpg\?cssauto/},
          ],
        },
      },
    },
  },
};

export default {
  id: 'byte-efficiency',
  expectations,
  config,
  runSerially: true,
};