1. Definition

Promises and async/await are both used to handle asynchronous operations in JavaScript. async/await is built on top of Promises and provides a more readable and cleaner way to write asynchronous code.

2. Promise

• Uses .then() and .catch()
• Supports chaining
• Can become complex with multiple chains
• Good for handling parallel operations

3. async/await

• Uses async and await keywords
• Looks like synchronous code
• Easier to read and maintain
• Uses try/catch for error handling

4. Key Differences

• Syntax: Promise → .then() | async/await → cleaner syntax
• Readability: async/await is more readable
• Error Handling: Promise → .catch() | async/await → try/catch
• Chaining: Promise supports chaining
• Debugging: async/await is easier to debug

5. Example Comparison

👉 Using Promise:

fetchData()
  .then(data => processData(data))
  .then(result => console.log(result))
  .catch(err => console.log(err));

👉 Using async/await:

async function getData() {
  try {
    const data = await fetchData();
    const result = await processData(data);
    console.log(result);
  } catch (err) {
    console.log(err);
  }
}

6. When to Use

• Use Promises for parallel operations (Promise.all)
• Use async/await for cleaner sequential code
• Use async/await in modern applications

7. Advantages

• Promises handle async operations
• async/await improves readability
• Better error handling