example using setTimeout to create a delayed, async function that is returned in a promise.

promise-example-async.js

//contrived example creating a delayed function and a function that returns a promise where the delayed functio is resolved.

const delay = (cb) => {
  setTimeout(() => {
    cb('delay over')
  }, 2000);
}

const promiseDelay = new Promise((resolve, reject) => {
	delay((message)=>{
 	 if (message){
  		resolve(message)
  	}else{
  		reject(Error('it broke'))
  	}
  })
})

//call function using async/ await
const asyncFunc = async () => {
	const message = await promiseDelay
  console.log(message)
}

//call function using then
promiseDelay.then(data => console.log(data))