index.js

const { chromium } = require("playwright");
const Sitemapper = require("sitemapper");
const { chunks } = require("./src/util");

const MAX_PAGES = 100;

const fetchSitemapUrls = async baseUrl => {
  const sitemap = new Sitemapper();
  const { sites } = await sitemap.fetch(`${baseUrl}/sitemap.xml`);
  const maxSites = Math.min(sites.length, MAX_PAGES);
  //TODO: sort by sitemap priority
  if (maxSites === 0) {
    return [baseUrl];
  }
  const absoluteUrlSites = sites.map(site => {
    if (site.startsWith("/")) {
      return `${baseUrl}${site}`;
    }
    return site;
  });
  return absoluteUrlSites.slice(0, maxSites);
};

const runAccessibilityTestsOnUrl = async url => {
  const browser = await chromium.launch();
  const context = await browser.newContext();
  try {
    const page = await context.newPage();
    await page.goto(url);
    await page.addScriptTag({
      url: "https://cdnjs.cloudflare.com/ajax/libs/axe-core/3.4.2/axe.min.js"
    });
    const axeViolations = await page.evaluate(async () => {
      const axeResults = await new Promise((resolve, reject) => {
        window.axe.run((err, results) => {
          if (err) {
            reject(err);
          } else {
            resolve(results);
          }
        });
      });

      return {
        violations: axeResults.violations.map(violation => ({
          id: violation.id,
          impact: violation.impact,
          description: violation.description,
          nodes: violation.nodes.map(node => node.html)
        }))
      };
    });
    return { url, ...axeViolations };
  } catch (e) {
    return { url, violations: [], error: e.message };
  } finally {
    await browser.close();
  }
};

const runAllChecks = async (urls, spinner) => {
  const chunkedUrls = [...chunks(urls, 5)];
  const totalViolationsByPage = [];
  for (const urlChunk of chunkedUrls) {
    if (spinner) {
      spinner.text = `Running accessibility checks... (${totalViolationsByPage.length ||
        1} of ${urls.length} pages)`;
    }
    const violationPromises = urlChunk.map(url =>
      runAccessibilityTestsOnUrl(url)
    );
    const resolvedViolationsByPage = await Promise.all(violationPromises);
    totalViolationsByPage.push(...resolvedViolationsByPage);
  }
  return totalViolationsByPage;
};

const lumberjack = async (baseUrl, options, spinner) => {
  const urls = options.baseUrlOnly
    ? [baseUrl]
    : await fetchSitemapUrls(baseUrl);
  return runAllChecks(urls, spinner);
};

module.exports = lumberjack;