add async await

index.js

@@ -338,3 +338,60 @@ asyncTask()
 	.catch(function onRejected(error) {
 		console.log(error.message);
 	});
+
+Promise.resolve(1)
+	.then((value) => {
+		console.log(value);
+		return value * 2;
+	})
+	.then((value) => {
+		console.log(value);
+		return value * 2;
+	})
+	.then((value) => {
+		console.log(value);
+		return value * 2;
+	});
+
+function delay(timeoutMs) {
+	return new Promise((resolve) => {
+		setTimeout(() => {
+			resolve(timeoutMs);
+		}, timeoutMs);
+	});
+}
+
+const racePromise = Promise.race([delay(1), delay(32), delay(64), delay(128)]);
+
+async function doAsync() {
+	return "value";
+}
+
+doAsync().then((value) => {
+	console.log(value);
+});
+
+function dummyFetch(path) {
+	return new Promise((resolve, reject) => {
+		setTimeout(() => {
+			if (path.startsWith("/resource")) {
+				resolve({ body: `Response body of ${path}` });
+			} else {
+				reject(new Error("NOT FOUND"));
+			}
+		}, 1000 * Math.random());
+	});
+}
+
+async function fetchAB() {
+	const results = [];
+	const responseA = await dummyFetch("/resource/A");
+	results.push(responseA.body);
+	const responseB = await dummyFetch("/resource/B");
+	results.push(responseB.body);
+	return results;
+}
+
+fetchAB().then((results) => {
+	console.log(results);
+});