Function checkIfCollectable

test/common/gc.js:92–127

(
  fn, maxCount = 4096, generateSnapshotAt = Infinity, logEvery = 128)

// other logic in V8 such as bytecode aging, and it can slow down the test
// significantly, so it should be used scarcely and only as a last resort.
async function checkIfCollectable(
  fn, maxCount = 4096, generateSnapshotAt = Infinity, logEvery = 128) {
  let anyFinalized = false;
  let count = 0;

  const f = new FinalizationRegistry(() => {
    anyFinalized = true;
  });

  async function createObject() {
    const obj = await fn();
    f.register(obj);
    if (count++ < maxCount && !anyFinalized) {
      setImmediate(createObject, 1);
    }
    // This can force a more thorough GC, but can slow the test down
    // significantly in a big heap. Use it with care.
    if (count % generateSnapshotAt === 0) {
      // XXX(joyeecheung): This itself can consume a bit of JS heap memory,
      // but the other alternative writeHeapSnapshot can run into disk space
      // not enough problems in the CI & be slower depending on file system.
      // Just do this for now as long as it works and only invent some
      // internal voodoo when we absolutely have no other choice.
      require('v8').getHeapSnapshot().pause().read();
      console.log(`Generated heap snapshot at ${count}`);
    }
    if (count % logEvery === 0) {
      console.log(`Created ${count} objects`);
    }
    if (anyFinalized) {
      console.log(`Found finalized object at ${count}, stop testing`);
    }
  }

  createObject();
}

// Repeat an operation and give GC some breathing room at every iteration.
async function runAndBreathe(fn, repeat, waitTime = 20) {