Q211- What is async/await and how is it different from Promises?

async/await is syntactic sugar built on top of Promises — it makes asynchronous code look and behave like synchronous code, improving readability and error handling.

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1️⃣ The async Keyword

• Declares a function that always returns a Promise.
• Inside an async function, you can use the await keyword.

async function greet() {
  return "Hello!";
}
greet().then(console.log); // Output: Hello!

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2️⃣ The await Keyword

• Used inside async functions to pause execution until a Promise resolves or rejects.
• Makes code look synchronous but still runs asynchronously.

async function fetchData() {
  const response = await fetch("https://jsonplaceholder.typicode.com/todos/1");
  const data = await response.json();
  console.log(data);
}
fetchData();

🕒 await waits for the Promise to resolve before moving to the next line.

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3️⃣ Error Handling

With Promises:

fetch("api/url")
  .then(res => res.json())
  .catch(err => console.error(err));

With async/await (cleaner):

async function getData() {
  try {
    const res = await fetch("api/url");
    const data = await res.json();
    console.log(data);
  } catch (err) {
    console.error("Error:", err);
  }
}

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4️⃣ Key Differences

Feature	Promises	async/await
Syntax	Uses .then() / .catch() chaining	Looks like synchronous code
Readability	Nested or chained	Cleaner and easier to follow
Error Handling	.catch()	try...catch
Underlying Mechanism	Built on Promises	Built on top of Promises

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💡 In Short:

async/await simplifies working with Promises by making asynchronous code look synchronous and easier to read and debug, but it still uses Promises under the hood.