Run results for: Await vs Then

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:97.0) Gecko/20100101 Firefox/97.0

Browser: Firefox 97

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Then	343532.9 Ops/sec
Await	76015.1 Ops/sec

Script Preparation code:

function foo(i) {
  return Promise.resolve(i+1);
}

function recur(i) {
  return i >= 10 ? Promise.resolve(i) : foo(i).then(recur);
}

function testThen() {
  return foo(0).then(recur);
}

async function testAwait() {
  let i = await foo(0);
  while (i < 10) {
    i = await foo(i);
  }
  
  return i;
}

Tests:

Then
testThen()
Await
testAwait();