Sequential promises

promises.js

// https://jrsinclair.com/articles/2019/how-to-run-async-js-in-parallel-or-sequential/

const job = (name, delay) =>
  new Promise((res) => {
    setTimeout(() => {
      console.log(`Job(${name}) resolving after ${delay}`);
      res();
    }, delay);
  });

// This does NOT work :(
["a", "b", "c"].forEach(async (i) => {
  await job(i, 1000);
});

// This DOES work :)
for (const i of ["a", "b", "c"]) {
  await job(i, 1000);
}

// These also work, but are ahrder to read imho

["a", "b", "c"].reduce(
  (a, i) => a.then(() => job(i, 1000)),
  Promise.resolve(null)
);

["a", "b", "c"].reduce(async (a, i) => {
  await a;
  return job(i, 1000);
}, Promise.resolve(null));