add eslint rules for promises #3796
Closed
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
✅ Deploy Preview for compassionate-pike-271cb3 ready!
To edit notification comments on pull requests, go to your Netlify site settings. |
|
Hi @yaacovCR, I'm @github-actions bot happy to help you with this PR 👋 Supported commandsPlease post this commands in separate comments and only one per comment:
|
|
This ends up being a "bug fix" because it does remove an extra tick and so is observable. |
yaacovCR
changed the title
yaacovCR
force-pushed
the
even-more
branch
2 times, most recently
from
660c90c to
b057bc9
Compare
IvanGoncharov
requested changes
Dec 14, 2022
yaacovCR
force-pushed
the
even-more
branch
4 times, most recently
from
da0a5a4 to
f1ba488
Compare
yaacovCR
force-pushed
the
even-more
branch
2 times, most recently
from
b66bdd3 to
1c39356
Compare
|
For simplicity, I have dropped the specialized helpers, provider just a single |
...and enable basic rules
leads to one less tick in `executeStreamField` in the branch where completion of a non-promise yields a promise.
errors avoided by previously avoiding then/catch
we can't fix then, but we can replace it. instead of using immediately invoked anonymous asynchronous arrow functions, we can replace the then method with then-like helper functions. In fact, we can optimize these small helpers to the exact cases we need. = after() => helper with only onFulfilled callback = catchAfter => helper with onError callback that handles promise rejection = tryAfter => helper with synchronous onFulfilled callback and onError callback that handles promise rejection and onFulfilled exceptions
Motivation: It is faster to await a promise prior to returning it from an async function than to return a promise with `.then()`. See: https://github.com/tc39/proposal-faster-promise-adoption Previously, this eslint rule errored by default only 'in-try-catch'.
`after` becomes sync, requiring no return type check for the onFulfilled result.
|
Closing this, see edited comment on #3754. The real world implications of the extra tick within |
yaacovCR
added a commit
to yaacovCR/graphql-js
that referenced
this pull request
Dec 27, 2022
We could not demonstrate via actual benchmarking that the tick reduction from awaiting a promise prior to returning it translates into real-world performance gains. See graphql#3796. In any case, the promise must be awaited (irrespective of performance) to allow the catch block to handle rejection errors. Simply returning `completed` would result in test failures.
yaacovCR
added a commit
that referenced
this pull request
Jan 2, 2023
We could not demonstrate via actual benchmarking that the tick reduction from awaiting a promise prior to returning it translates into real-world performance gains. See #3796. In any case, the promise must be awaited (irrespective of performance) to allow the catch block to handle rejection errors. Simply returning `completed` would result in test failures.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
UPDATE:
After much testing, I am unable to generalize the speed savings from #3754, so this PR has been closed.
See #3754 for further discussion.
prefer-await-over-promises helps avoid extra ticks, formalizing the optimization from #3754 across the board
various additional rules add additional best practices with regard to promise use with at most trivial code changes