java-script-promises-with-async-await-and-loops-0-one-second-counter.js

// promisified 'setTimeout' function
function delay(delayedFunction, time) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      try {
        resolve(delayedFunction());
      } catch (error) {
        reject(error.message);
      }
    }, time);
  });
}

// top-level async declaration
async function main() {
  // await using a for...of loop
  const delaysInMs = [3000, 2000, 1000];

  for (const time of delaysInMs) {
    console.log(await delay(() => `print after ${time / 1000} second(s)`, time));
  }

  // await using a while loop
  let count = 0;
  const max = 100;

  while (count < max) {
    const result = await delay(() => `${++count} of ${max} lines...`, 1000);
    console.log(result);
  }
}

main();