Create async-await.js

async-await.js

@@ -0,0 +1,42 @@
+// Basic understanding for async-await, experiment!
+
+// waiting for value
+const wait = (time) => {
+ // setTimeout doesnt return promise so need to return one
+ return new Promise((resolve, reject) => {
+ setTimeout(() => {
+ console.log(time);
+ resolve();
+ }, time);
+ });
+};
+
+const firstTimeout = async (f) => {
+ console.log("run 1");
+ return await wait(f);
+};
+
+const secondTimeout = async () => {
+ console.log("run 2");
+ await wait(2000);
+ return 2000;
+};
+
+const thirdTimeout = async () => {
+ console.log("run 3");
+ await wait(3000);
+ return 1000;
+};
+
+const main = async () => {
+ console.log("hi"); // print first
+ // wait for value to use
+ // https://stackoverflow.com/questions/48617486/why-async-await-doesnt-work-in-my-case
+ // await only suspends when the value passed to it is a Promise.
+ // In your case, setTimeout returns a Number so await doesn't wait for it.
+ let f = await thirdTimeout();
+ let s = await firstTimeout(f);
+ secondTimeout(s);
+ console.log("test"); // print last
+};
+main();