When working with asynchronous code in JavaScript, you often face a choice between using the older .then chaining style with Promises and the newer async/await syntax. Both approaches allow you to handle asynchronous operations, but they differ significantly in how readable and maintainable your code becomes, especially as complexity increases.

With traditional Promise chaining, you use the .then method to handle the result of a Promise. Each asynchronous step is nested within another .then, which can quickly become hard to follow when you have multiple dependent asynchronous operations. Error handling is usually managed with a .catch at the end of the chain, but if you need to handle errors at specific steps, the code can become even more complicated.

Async/await simplifies the syntax for working with Promises by allowing you to write asynchronous code that looks much like synchronous code. When you use await, JavaScript pauses the execution of your function until the Promise resolves, then returns the result. This makes it much easier to read and reason about the flow of your program.

Notice how the async/await version reads from top to bottom, just like synchronous code, making the logic much easier to trace. Error handling is also more straightforward, as you can use a single try/catch block to manage exceptions for all awaited operations inside the function.