week2-01 hard problems

week-2/01-async-js/hard (promises)/1-promisify-setTimeout.js

@@ -3,6 +3,11 @@
 */
 
 function wait(n) {
+  return new Promise((resolve) => {
+    setTimeout((_) => {
+      resolve();
+    }, n * 1000);
+  });
 }
 
 module.exports = wait;

week-2/01-async-js/hard (promises)/2-sleep-completely.js

@@ -5,6 +5,9 @@
  */
 
 function sleep(milliseconds) {
+  return new Promise((res) => {
+    setTimeout(res, milliseconds);
+  });
 }
 
 module.exports = sleep;

week-2/01-async-js/hard (promises)/3-promise-all.js

@@ -5,19 +5,28 @@
  */
 
 function wait1(t) {
-
+  return new Promise((res) => {
+    setTimeout(res, t * 1000);
+  });
 }
 
 function wait2(t) {
-
+  return new Promise((res) => {
+    setTimeout(res, t * 1000);
+  });
 }
 
 function wait3(t) {
-
+  return new Promise((res) => {
+    setTimeout(res, t * 1000);
+  });
 }
 
 function calculateTime(t1, t2, t3) {
-
+  const start = Date.now();
+  return Promise.all([wait1(t1), wait2(t2), wait3(t3)]).then(
+    () => Date.now() - start
+  );
 }
 
 module.exports = calculateTime;

week-2/01-async-js/hard (promises)/4-promise-chain.js

@@ -5,20 +5,32 @@
  * Compare it with the results from 3-promise-all.js
  */
 
-function wait1(t) {
+const wait = require("./1-promisify-setTimeout");
 
+function wait1(t) {
+  return new Promise((res) => {
+    setTimeout(res, t * 1000);
+  });
 }
 
 function wait2(t) {
-
+  return new Promise((res) => {
+    setTimeout(res, t * 1000);
+  });
 }
 
 function wait3(t) {
-
+  return new Promise((res) => {
+    setTimeout(res, t * 1000);
+  });
 }
 
 function calculateTime(t1, t2, t3) {
-
+  const start = Date.now();
+  return wait1(t1)
+    .then(() => wait2(t2))
+    .then(() => wait3(t3))
+    .then(() => Date.now() - start);
 }
 
 module.exports = calculateTime;