TIP: When making two asynchronous calls, ask yourself if you want to make those calls in serial or parallel

parallel-async.js

// code: https://twitter.com/joelnet/status/1231994830798061568
const sum = (a, b) => Promise.resolve(a + b);
const subtract = (a, b) => Promise.resolve(a - b);

// Promises
const promises = async () => {
  const p1 = sum(7, 3);
  const p2 = sum(8, 5);

  return Promise.all([p1, p2]);
}

// Async - await
const asyncs = async () => {
  const p1 = await sum(8, 5);
  const p2 = await sum(7, 3);

  // if you check out the thread, then:
  // return await Promise.all([p1, p2]);
  return [await p1, await p2];
};