Record v8 coverage for repros

coverage-record.ts

import inspector from "node:inspector/promises";
import { writeFileSync } from "node:fs";

const target = "coverage-target.mjs";
writeFileSync(
  target,
  `\
// Repro code here
`,
  "utf-8",
);

const session = new inspector.Session();

const coverage = await recordCoverage(async () => {
  await import(`./${target}`);
});

console.log(JSON.stringify(coverage, null, 2));

export async function recordCoverage(method: () => Promise<void>) {
  session.connect();
  await session.post("Profiler.enable");
  await session.post("Profiler.startPreciseCoverage", {
    callCount: true,
    detailed: true,
  });

  await method();

  const { result } = await session.post("Profiler.takePreciseCoverage");

  await session.post("Profiler.stopPreciseCoverage");
  await session.post("Profiler.disable");
  session.disconnect();

  return result.find(({ url }) => url.endsWith("coverage-target.mjs"));
}