Async/await example

async-await.js

asyncAwaitTest();

async function asyncAwaitTest() {
	let result1, result2, result3, results;
	try {
		result1 = promise1();
		result2 = promise2();
		result3 = promise3();
		results = [await result1, await result2, await result3];
	} catch(err) {
		console.error('dang');
	}
	console.log(results);
}

function promise1() {
	return new Promise(resolve => {
		console.log('promise1 start');
		setTimeout(() => {
			console.log('promise1 done');
			resolve('promise1');
		}, 100);
	});
}

function promise2() {
	return new Promise(resolve => {
		console.log('promise2 start');
		setTimeout(() => {
			console.log('promise2 done');
			resolve('promise2');
		}, 300);
	});
}

function promise3() {
	return new Promise(resolve => {
		console.log('promise3 start');
		setTimeout(() => {
			console.log('promise3 done');
			resolve('promise3');
		}, 200);
	});
}