async javascript test

test.js

const MAX_INFLIGHT = 4;
const TOTAL = 100;
// the given dummy api supports a maximum of 4 of inflight requests.
// the given code is correct, but it is slow because it processes elements serially.
// your task is to process 100 elements as fast as possible.
// run this code with "node/bun test.js".
// it should print "pass".
// no external dependencies are allowed.
async function run(elements) {
  // ============
  // your code here starts here
  const results = [];
  for (const element of elements) {
    const result = await api(element);
    results.push(result);
  }
  return results;
  // your code ends here
  // ============
}
// api accepts 1 element, takes some time, returns a processed element
const api = (function () {
  let inflight = 0;
  const sleep = (ms) => new Promise((done) => setTimeout(done, ms));
  return async (element) => {
    inflight++;
    if (inflight > MAX_INFLIGHT) {
      console.log(`too many requests`);
      process.exit(1);
    }
    const delay =
      Math.random() < 0.1 ? 1000 : 100 + (Math.random() - 0.5) * 100;
    await sleep(delay);
    inflight--;
    console.log(`processed element ${element}/${TOTAL}`);
    return "P" + element;
  };
})();
// check ensures you have processed all elements correctly
function check(results) {
  for (let i = 0; i < TOTAL; i++) {
    const got = results[i];
    const expect = "P" + (i + 1);
    if (got !== expect) {
      console.log(`expected result[${i}] to be ${expect}, got ${got}`);
      process.exit(1);
    }
  }
  console.log("pass");
}
// create elements, run user code, check results
const elements = new Array(TOTAL).fill(null).map((_, i) => i + 1);
run(elements).then(check);

var total = 100;
var array = [...Array(4)];
async function fn() {
  return new Promise((resolve, reject) => setTimeout((Math.random() < .5 ? resolve : reject), Math.floor(Math.random() * 1000)))
    .then(() => (--total, ({
      completed: 1,
      resolved: 1,
      rejected: 0,
      pending: 0
    }))).catch(() => (--total, ({
      completed: 1,
      rejected: 1,
      resolved: 0,
      pending: 0
    })))
}
while (total) {
  await Promise.allSettled(array.map(fn));
}