// start logging
// log 42
// process 42
Promise.resolve(42)
  .tap(x => asyncLogging(x))
  .then(x => console.log(`process ${x}`));

function asyncLogging(x) {
  console.log('start logging');

  return new Promise(resolve => setTimeout(() => {
    console.log(`log ${x}`);
    resolve();
  }, 1000));
}