findIndexAsync.js

findIndexAsync.js

async function findIndexAsync(promises, predicate) {
  let i = 0;
  for await (const p of asyncIterate(promises)) {
    if (predicate(p)) {
      return i;
    }
    i++;
  }
}

async function* asyncIterate(promises) {
  for (const p of promises) {
    yield p;
  }
}

const promises = [Promise.resolve(false), Promise.resolve(true)];
(async () => {
  console.log(await findIndexAsync(promises, (v) => v));
})();