How does async/await map onto the microtask queue under the hood?

An async function returns immediately at its first await, suspending execution; the code after await is scheduled to resume as a microtask once the awaited Promise settles — functionally equivalent to chaining .then() callbacks, just with more readable syntax.

async function run() {
  console.log('1');
  await null; // yields, resumes as a microtask
  console.log('2');
}
run();
console.log('3');
// logs: 1, 3, 2