Async/Await

1// Basic async function
2async function fetchData(): Promise<string> {
3  return "Data fetched!";
4}
5 
6// Async function with await
7interface User {
8  id: number;
9  name: string;
10  email: string;
11}
12 
13async function getUser(id: number): Promise<User> {
14  // Simulating API call
15  await new Promise((resolve) => setTimeout(resolve, 100));
16 
17  return {
18    id,
19    name: `User ${id}`,
20    email: `user${id}@example.com`,
21  };
22}
23 
24// Error handling with try/catch
25async function getUserSafely(id: number): Promise<User | null> {
26  try {
27    const user = await getUser(id);
28    return user;
29  } catch (error) {
30    console.error("Failed to fetch user:", error);
31    return null;
32  }
33}
34 
35// Sequential async operations
36async function processUsers(ids: number[]): Promise<User[]> {
37  const users: User[] = [];
38 
39  for (const id of ids) {
40    const user = await getUser(id);
41    users.push(user);
42    console.log(`Processed: ${user.name}`);
43  }
44 
45  return users;
46}
47 
48// Parallel async operations
49async function processUsersParallel(ids: number[]): Promise<User[]> {
50  const userPromises = ids.map((id) => getUser(id));
51  const users = await Promise.all(userPromises);
52  return users;
53}
54 
55// Async IIFE (Immediately Invoked Function Expression)
56(async () => {
57  console.log("Starting...");
58 
59  const user = await getUser(1);
60  console.log(`Got user: ${user.name}`);
61 
62  const users = await processUsersParallel([2, 3, 4]);
63  console.log(`Got ${users.length} users in parallel`);
64 
65  console.log("Done!");
66})();