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Web Performance Optimization & Lighthouse · Pelajaran

Audit dan Pernyataan Khusus

Kembangkan audit Lighthouse Anda sendiri untuk menerapkan aturan kinerja atau praktik terbaik tertentu yang relevan dengan proyek Anda.

Audit dan Pernyataan Khusus adalah pelajaran Web Performance Optimization & Lighthouse gratis di CoddyKit. Ini adalah pelajaran 2 dari 4. Kamu bisa membaca pelajaran lengkapnya di bawah secara gratis — lalu praktikkan langsung di browser dengan editor kode bawaan dan tutor AI 24/7. Ini adalah bagian dari jalur belajar Web Performance Optimization & Lighthouse, dan progresmu tersinkronisasi di web dan aplikasi CoddyKit. Kursus Web Performance Optimization & Lighthouse mencakup 4 pelajaran total.

Bagian dari pelajaran ini belum diterjemahkan dan ditampilkan dalam bahasa Inggris.

Extend Lighthouse's Power

Welcome to creating custom Lighthouse audits! While Lighthouse offers many built-in checks, sometimes you need to enforce project-specific rules or validate unique performance requirements.

This lesson shows you how to build your own.

Why Create Custom Audits?

Custom audits allow you to tailor Lighthouse to your exact needs. They help you:

  • Enforce Standards: Check for specific coding patterns or component usage.
  • Validate Unique Metrics: Measure performance aspects not covered by default.
  • Ensure Compliance: Verify project-specific accessibility or SEO rules.
  • Automate Checks: Integrate tailored performance feedback directly into your development workflow.

Audit Anatomy: Gatherers & Audits

A custom Lighthouse audit typically has two main parts:

  • Gatherer: This component collects raw data about the page. It runs inside the browser and extracts specific information, like DOM elements, network requests, or JavaScript variables.
  • Audit: This component analyzes the data collected by the gatherer. It applies logic to determine a score, a pass/fail state, and provides recommendations.

Both are then linked in a Lighthouse configuration file.

Building a Gatherer: Data Collection

A gatherer is responsible for collecting data. It extends Lighthouse.Gatherer and uses methods like afterPass to run JavaScript in the page's context.

Let's create a gatherer that checks for a specific <meta> tag.

Gatherer Code Example

This gatherer looks for an <meta name="author"> tag and returns its content. If not found, it returns null.

// gatherers/author-meta-gatherer.js
'use strict';
const Gatherer = require('lighthouse').Gatherer;

class AuthorMetaGatherer extends Gatherer {
  afterPass(options) {
    const driver = options.driver;
    // Evaluate JS in the browser context
    return driver.evaluateAsync(() => {
      const metaTag = document.querySelector('meta[name="author"]');
      return metaTag ? metaTag.content : null;
    });
  }
}

module.exports = AuthorMetaGatherer;

Building an Audit: Evaluation Logic

An audit takes the data provided by gatherers and applies your custom logic. It extends Lighthouse.Audit and implements a static audit method.

This method receives the collected "artifacts" (data) and determines the audit's result.

Audit Code Example

This audit uses the data from our AuthorMetaGatherer to check if the author meta tag is present and has content. It scores 1 (pass) or 0 (fail).

// audits/author-meta-audit.js
'use strict';
const Audit = require('lighthouse').Audit;

class AuthorMetaAudit extends Audit {
  static get meta() {
    return {
      id: 'author-meta-tag',
      title: 'Author meta tag is present',
      failureTitle: 'Author meta tag is missing or empty',
      description: 'Ensures an author meta tag is present for attribution.',
      requiredArtifacts: ['AuthorMetaGatherer'],
    };
  }

  static audit(artifacts) {
    const authorMetaContent = artifacts.AuthorMetaGatherer;
    const passed = !!authorMetaContent && authorMetaContent.trim().length > 0;

    return {
      score: passed ? 1 : 0,
      details: {
        type: 'debuginfo',
        headings: [
          {key: 'content', itemType: 'text', text: 'Author Meta Content'},
        ],
        items: [{content: authorMetaContent || 'Not found'}],
      },
    };
  }
}

module.exports = AuthorMetaAudit;

Integrating into Lighthouse Config

To make Lighthouse aware of your custom gatherer and audit, you need a custom configuration file. This file tells Lighthouse which gatherers to run and which audits to include, often extending the default Lighthouse checks.

// custom-config.js
'use strict';

module.exports = {
  extends: 'lighthouse:default', // Inherit default audits
  gatherers: [
    './gatherers/author-meta-gatherer.js',
  ],
  audits: [
    './audits/author-meta-audit.js',
  ],
  categories: {
    'custom-category': {
      title: 'Custom Checks',
      description: 'Project-specific performance and best practice audits.',
      auditRefs: [
        {id: 'author-meta-tag', weight: 1, group: 'metrics'},
      ],
    },
  },
};

Running Lighthouse with Custom Audits

Finally, you can run Lighthouse programmatically using Node.js, referencing your custom configuration file. This script launches Chrome, runs Lighthouse, and generates a report.

Make sure you have lighthouse and chrome-launcher installed via npm.

// run-custom-audit.js
const lighthouse = require('lighthouse');
const chromeLauncher = require('chrome-launcher');

(async () => {
  const chrome = await chromeLauncher.launch({chromeFlags: ['--headless']});
  const options = {
    logLevel: 'info',
    output: 'html',
    onlyCategories: ['custom-category'], // Run ONLY our custom category
    port: chrome.port
  };
  const config = require('./custom-config.js'); // Load your custom config

  const runnerResult = await lighthouse('https://example.com', options, config);

  console.log('Report is done for', runnerResult.lhr.requestedUrl);
  // Accessing your custom audit score:
  const customAuditScore = runnerResult.lhr.audits['author-meta-tag'].score;
  console.log('Author Meta Tag Audit Score:', customAuditScore);

  await chrome.kill();
})();

Custom Audit Components

You've learned about the key pieces needed to build a custom Lighthouse audit.

Which of the following are essential components when creating a custom Lighthouse audit?

Recap: Your Custom Audit Toolkit

You've successfully learned how to extend Lighthouse's capabilities!

By understanding gatherers, audits, and custom configurations, you can now build powerful, project-specific checks. This allows you to enforce unique best practices and gain deeper, tailored insights into your web performance.

Pertanyaan yang Sering Diajukan

Apakah pelajaran “Audit dan Pernyataan Khusus” gratis?

Ya — teks lengkap “Audit dan Pernyataan Khusus” gratis dibaca di sini di web. Untuk praktiknya secara interaktif (editor kode bawaan dan tutor AI 24/7) dan buka sisa kursus Web Performance Optimization & Lighthouse, upgrade ke CoddyKit PRO. Kursus Web Performance Optimization & Lighthouse mencakup 4 pelajaran total.

Apa yang akan aku pelajari di “Audit dan Pernyataan Khusus”?

Kembangkan audit Lighthouse Anda sendiri untuk menerapkan aturan kinerja atau praktik terbaik tertentu yang relevan dengan proyek Anda. Kamu berlatih Web Performance Optimization & Lighthouse dengan kode praktik yang langsung kamu jalankan di browser, dan tutor AI 24/7 menjawab pertanyaanmu saat kamu mengerjakan pelajaran ini.

Apakah aku perlu pengalaman untuk memulai Web Performance Optimization & Lighthouse?

Tidak diperlukan pengalaman sebelumnya. Web Performance Optimization & Lighthouse di CoddyKit dirancang untuk pemula hingga pelajar tingkat lanjut, jadi kamu bisa memulai di sini atau dari awal dan belajar sesuai kecepatan kamu sendiri. Ini adalah pelajaran 2 dari 4.

Berapa lama pelajaran “Audit dan Pernyataan Khusus” memakan waktu?

Sebagian besar pelajaran CoddyKit memakan waktu sekitar 5–10 menit. Setiap pelajaran ringkas dan interaktif, jadi kamu membuat kemajuan stabil dan melanjutkan dari tempat kamu tinggalkan di web dan aplikasi.

Bisakah aku menulis dan menjalankan kode dalam pelajaran Web Performance Optimization & Lighthouse ini?

Ya. Setiap pelajaran Web Performance Optimization & Lighthouse menyertakan editor kode bawaan, jadi kamu menulis dan menjalankan kode nyata langsung di browser dan mendapatkan umpan balik AI instan — tidak diperlukan penyiapan lokal.

Semua pelajaran dalam kursus ini

  1. Lighthouse melalui CLI dan Secara Terprogram
  2. Audit dan Pernyataan Khusus
  3. Mengintegrasikan Lighthouse ke dalam CI/CD
  4. Anggaran Performa dengan Lighthouse
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