sleep (await version)

sleep.js

var sleep = (ms) => new Promise(resolve => setTimeout(resolve, ms));

// Usage
//  within an 'async' function
await sleep(2000);

// And without async?
//   scenarios like the following do not work unfortunately
console.log('Wait for 5s...');
(async function() {
  await sleep(5000);
})();  
console.log('OK! Waited 5s');

// indeed, you should have an async which is precisely what you want to avoid
console.log('Wait for 5s...');
await (async function() {
  await sleep(5000);
})();  
console.log('OK! Waited 5s');