Interface Coverage

Coverage gathers information about parts of JavaScript and CSS that were used by the page.

An example of using JavaScript coverage to produce Istanbul report for page load:

NOTE Coverage APIs are only supported on Chromium-based browsers.

const { chromium } = require('playwright');
const v8toIstanbul = require('v8-to-istanbul');

(async() => {
  const browser = await chromium.launch();
  const page = await browser.newPage();
  await page.coverage.startJSCoverage();
  await page.goto('https://chromium.org');
  const coverage = await page.coverage.stopJSCoverage();
  for (const entry of coverage) {
    const converter = v8toIstanbul('', 0, { source: entry.source });
    await converter.load();
    converter.applyCoverage(entry.functions);
    console.log(JSON.stringify(converter.toIstanbul()));
  }
  await browser.close();
})();