Basic JS Async Cookbook

function asleep(delay) {
	return new Promise(resolve => setTimeout(resolve, delay));
}

// Usage:
await asleep(1000);

function aalert(message) {
	return new Promise( resolve => resolve(alert(message)) );
}
function aconfirm(message) {
	return new Promise( resolve => resolve(confirm(message)) );
}
function aprompt(message, deflt) {
	return new Promise( resolve => resolve(prompt(message, deflt)) );
}

// Usage:
await aalert("The task will begin as soon as you press OK.") ; do_task();
aalert("The task will begin as soon as you press OK.").then(do_task);

if( await aconfirm("Do you want to do the task?") ) do_task();
aconfirm("Do you want to do the task?").then( response => response ? do_task() : undefined );

username = await aprompt("Enter your username.");

// aXMLHttpRequest: a "handmade" version of fetch, for educational purposes
function aXMLHttpRequest(method, location, responseType="", body=undefined) {
	return new Promise( (resolve, reject) => {
		const xhr = new XMLHttpRequest();
		xhr.open(method, location, true);
		xhr.responseType = responseType;
		xhr.onload = resolve;
		xhr.onerror = reject;
		xhr.send(body);
		return xhr;
	});
}

I'll happily take suggestions/requests for more recipes here in the comments!