finalization-registry.js

let counter = 0;
const registry = new FinalizationRegistry(() => {
  console.log(`Array gets garbage collected at ${counter}`);
});

(function allocateMemory() {
  // Allocate 50000 functions — a lot of memory!
  registry.register(Array.from({ length: 50000 }, () => () => {}));
  if (counter > 1000) {
    console.log("Main job ends");
    return;
  }
  counter++;
  // Use setTimeout to make each allocateMemory a different job
  setTimeout(allocateMemory, 10);
})();