I want to write a callback that takes a bit of time to complete an external IO operation, but I do not want it to interfere when sending data back to the client. I don't care about waiting for callback completion for purposes of the reply back to the client, but if the callback results in an error, I would like to log it. About 80% of executions will result in this callback executing after the response is sent back to the client and the connection is closed.
My approach works well and I have not seen any problems, but I would like to know whether there are any pitfalls in this approach that I may be unaware of. I would think that node's evented IO would handle this without issue, but I want to make sure before I commit this architecture to production. Any issues that should make me reconsider this approach?
As long as you're not trying to reference that response object after the response is sent, this will not cause any problems. There's nothing special about a request handler that cares one bit about callbacks in its code being invoked after the response is generated.