fix(kvs): prevent overwriting localStorage during Initial state #398
Conversation
This file contains hidden or 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
kitlangton
force-pushed
the
fix/kvs-initial-state-overwrite
branch
3 times, most recently
from
e0b19e8 to
1e6b2ed
Compare
The kvs atom was writing the default value to storage during the Initial state, before the async load completed. This corrupted any existing stored data, causing values to reset on page reload. The fix removes the code that wrote the default to storage. The original code had a `Result.isSuccess` check around the write, but since Effect.flatten unwraps the Option from KeyValueStore.get, Success always contains a value and we'd return early - making that write unreachable. The Result.value() + Option.isSome() pattern is preserved to correctly handle previousSuccess when a refresh fails. Includes test that verifies storage isn't corrupted by the default value during async loading.
kitlangton
force-pushed
the
fix/kvs-initial-state-overwrite
branch
from
1e6b2ed to
3e6e4bd
Compare
Contributor
Author
|
I ran into this issue a few times on https://effect.institute |
tim-smart
requested changes
Jan 13, 2026
| return value.value | ||
| } | ||
| const defaultValue = options.defaultValue() | ||
| get.set(setAtom, defaultValue) |
Owner
There was a problem hiding this comment.
It needs to be set in some way, as the defaultValue is lazy and should only be evaluated once.
Cache the default value in atom state so it is evaluated once while the store is loading. Add a regression test to cover memoization behavior.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.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.
Summary
Atom.kvswould overwrite existing localStorage data during the Initial stateChanges
Result.isSuccess(result)check before writing default to storageTest plan