What’s wrong with awaiting a promise chain?

by

I’m being told awaiting a promise chain will break things in my code.

Not necessarily, your two code snippets do indeed work the same (as long as someFunction() really returns a promise).

What does it matter which one is used. What dangers does the first snippet introduce that the second one doesn’t?

It’s harder to understand and maintain, it’s confusing to mix different styles. Confusion leads to bugs.

Consider that you would need to add another promise call at the location of the console.log() call, or even a conditional return from the function. Can you use await in the callback like elsewhere in the function, do you need to return the result from the then callback, is it even possible to return from the outer function? All these questions don’t even come up in the first snippet. And while they can be easily answered for your toy example, it might not be as easy in real code with more complex and nested control flow.

So you should prefer the more concise and clean one. Stick to await for consistency, avoid then in async functions1.

1: Of course, there’s always an exception to the rule. I would say that it’s cleaner to use promise chaining for error handling in some cases where you would use catch or the second then callback.

More Related Contents:

  1. Async function returning promise, instead of value
  2. Use async await with Array.map
  3. Correct Try…Catch Syntax Using Async/Await
  4. Waiting for more than one concurrent await operation
  5. Can I fire and forget a promise in nodejs (ES7)?
  6. async/await always returns promise
  7. How to turn this callback into a promise using async/await?
  8. Using async/await with a forEach loop
  9. What is the difference between JavaScript promises and async await?
  10. Syntax for an async arrow function
  11. How to wait for a JavaScript Promise to resolve before resuming function?
  12. How to async await in react render function?
  13. Can’t throw error from within an async promise executor function
  14. for await of VS Promise.all
  15. JavaScript array .reduce with async/await
  16. Why do I need to await an async function when it is not supposedly returning a Promise?
  17. Slowdown due to non-parallel awaiting of promises in async generators
  18. using async await and .then together
  19. How to implement a pseudo blocking async queue in JS/TS?
  20. Do Javascript promises block the stack
  21. Javascript – if with asynchronous case
  22. What are asynchronous functions in JavaScript? What is “async” and “await” in JavaScript?
  23. Wait promise inside for loop
  24. Difference of using async / await vs promises?
  25. Async Await map not awaiting async function to complete inside map function before mapping next item
  26. How can I Interleave / merge async iterables?
  27. Implement async/await in sort function of arrays javascript
  28. Can I catch an error from async without using await?
  29. Using promise function inside Javascript Array map
  30. When does async function actually return a pending promise?

Leave a Comment