Document how to use with puppeteer?

• Version: 12.13.0
• Platform: Darwin Stevens-Mac-mini.local 19.0.0 Darwin Kernel Version 19.0.0: Thu Oct 17 16:17:15 PDT 2019; root:xnu-6153.41.3~29/RELEASE_X86_64 x86_64

Previously, with nyc, I was using puppeteer-to-istanbul, but now I’m not sure what to do. c8 needs to receive the reports from puppeteer somehow.

[queengooborg]

I was able to get puppeteer working with c8, thanks to https://github.com/puppeteer/puppeteer/pull/6454! I wanted to leave the code I used here for anyone else who may want to stick with puppeteer. The trick is to set the includeRawScriptCoverage to true in your startJSCoverage() options, and then write its output to JSON files. Huge thanks to @bricss for providing a foundation for me to work off of!

The code I wrote is as follows:

await page.coverage.startJSCoverage({includeRawScriptCoverage: true});

// Do your tests...

const jsCoverage = await page.coverage.stopJSCoverage();

// Point to original .js files
const coverage = jsCoverage
  .map(({rawScriptCoverage: it}) => ({
    ...it,
    scriptId: String(it.scriptId),
    url: it.url.replace(
      new RegExp(`${ origin }(?<pathname>.*)`),
      (...[, , , , { pathname }]) => `${
        pathname.match(/^\/src/)
        ? process.cwd()
        : path.resolve(dirPath, base)
      }${ pathname.replace(/([#?].*)/, '')
                  .replace(/\//g, path.sep) }`,
  })));

// Export coverage data
jsCoverage.forEach((it, idx) =>
  fs.writeFileSync(
    `${
      process.env.NODE_V8_COVERAGE
    }/coverage-${Date.now()}-${idx}.json`,
    JSON.stringify({result: [it]})
  )
);

[bcoe]

@queengooborg this is slick, we should document how to do this 😄