microtask の検証コード(無限ループを引き起こす)

micro task infinite loop.js

var callback;
var p = new Promise(resolve => callback = resolve);
var p2;
var microtask = () => {
  console.log("microtask");
  p2.then(microtask);
};
p2 = p.then(microtask);

console.log("sync");
setTimeout(() => console.log("setTimeout"));
requestAnimationFrame(() => console.log("requestAnimationFrame"));
callback();
console.log("sync2");