[sosek108]

Details

Stacked on Expensify#862's branch (feature/onyx-store-useonyxstate-recut).

useOnyxState ran its selector on every render, not only after a store change. React calls getSnapshot during render and again in its post-commit check, so a component re-rendered by its parent ran the selector about twice per render, reading every key through the state Proxy. The previousState effect had no deps, so it also built a new Proxy after every render. In a list where a parent re-renders every row, this cost repeats for every row. Plain useOnyx doesn't pay it, because useSyncExternalStoreWithSelector skips the selector when the snapshot reference is unchanged.

This PR makes getSnapshot return the previous output when the selector, the previousState view and every dep are the same references as last time. The previousState effect now runs only when the output changes, and is skipped for selectors declared with only (state), since they can't read previousState. A key the selector reads but doesn't list in dependencies can now go stale, and the dependencies doc says so.

On device (ManualSendMessageVisible, report actions list with useOnyxState rows), the App branch went from 212 ms before this change to 135.8 ms mean after it, against 159.4 ms on main from the same base.

Related Issues

GH_LINK

Linked E/App PR

Automated Tests

Added 3 tests to tests/unit/useOnyxStateTest.tsx (describe('re-render without a store change')):

• should not run the selector again when the component re-renders and no dependency changed (fails on the old hook: 7 calls instead of 3)
• should run the selector again when a re-render passes a new selector
• should run the selector again on a re-render after a dependency changed

Manual Tests

Pinned the change into the App branch that moves report actions list rows to useOnyxState and measured ManualSendMessageVisible on device: main 159.4 ms mean (20 spans), branch 135.8 ms mean (19 spans).

Author Checklist

• I linked the correct issue in the ### Related Issues section above
• I linked the corresponding Expensify/App PR in the ### Linked E/App PR section above, and verified this change against it (E/App CI passed and manual testing completed)
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android / native
  • Android / Chrome
  • iOS / native
  • iOS / Safari
  • MacOS / Chrome / Safari
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I followed proper code patterns (see Reviewing the code)
  • I verified that any callback methods that were added or modified are named for what the method does and never what callback they handle (i.e. toggleReport and not onIconClick)
  • I verified that the left part of a conditional rendering a React component is a boolean and NOT a string, e.g. myBool && <MyComponent />.
  • I verified that comments were added to code that is not self explanatory
  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
  • I verified proper file naming conventions were followed for any new files or renamed files. All non-platform specific files are named after what they export and are not named "index.js". All platform-specific files are named for the platform the code supports as outlined in the README.
  • I verified the JSDocs style guidelines (in STYLE.md) were followed
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I followed the guidelines as stated in the Review Guidelines
• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• I verified any variables that can be defined as constants (ie. in CONST.js or at the top of the file that uses the constant) are defined as such
• I verified that if a function's arguments changed that all usages have also been updated correctly
• If a new component is created I verified that:
  • A similar component doesn't exist in the codebase
  • All props are defined accurately and each prop has a /** comment above it */
  • The file is named correctly
  • The component has a clear name that is non-ambiguous and the purpose of the component can be inferred from the name alone
  • The only data being stored in the state is data necessary for rendering and nothing else
  • If we are not using the full Onyx data that we loaded, I've added the proper selector in order to ensure the component only re-renders when the data it is using changes
  • For Class Components, any internal methods passed to components event handlers are bound to this properly so there are no scoping issues (i.e. for onClick={this.submit} the method this.submit should be bound to this in the constructor)
  • Any internal methods bound to this are necessary to be bound (i.e. avoid this.submit = this.submit.bind(this); if this.submit is never passed to a component event handler like onClick)
  • All JSX used for rendering exists in the render method
  • The component has the minimum amount of code necessary for its purpose, and it is broken down into smaller components in order to separate concerns and functions
• If any new file was added I verified that:
  • The file has a description of what it does and/or why is needed at the top of the file if the code is not self explanatory
• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.
• I have checked off every checkbox in the PR author checklist, including those that don't apply to this PR.

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari