promises

src/07-funktionsprogrammierung/promises.ts

@@ -0,0 +1,43 @@
+const myPromise = new Promise<number>((resolve, reject) => {
+  reject('unknown error');
+  setTimeout(() => {
+    resolve(42);
+  }, 1000);
+});
+
+// myPromise
+//   .then((result) => {
+//     console.log(result);
+//     return result + 1;
+//   })
+//   .then((data) => console.log('new data: ', data))
+//   .catch((error) => console.error('Fehler: ', error))
+//   .finally(() => console.log('Promise abgeschlossen'));
+
+async function fetchData() {
+  try {
+    const result = await myPromise;
+    console.log('Daten empfangen: ', result);
+  } catch (error) {
+    console.log('Fehler: ', error);
+  }
+}
+
+fetchData();
+
+const promise1 = new Promise((resolve) => setTimeout(() => resolve('A'), 1000));
+const promise2 = new Promise((resolve) => setTimeout(() => resolve('B'), 2000));
+
+async function fetchAll() {
+  const results = await Promise.all([promise1, promise2]);
+  console.log(results);
+}
+
+fetchAll();
+
+async function fetchFirst() {
+  const result = await Promise.race([promise1, promise2]);
+  console.log('Fetch First: ', result);
+}
+
+fetchFirst();