`shallow` doesn't correctly compare different object instances if they only have property getters

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
52/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
react, typescript
Domain
frontend

Research direction

Start by locating the store's shallow implementation and its existing tests. Reproduce the reported comparison with two distinct objects that expose values through getters, then add coverage and adjust the behavior so distinct instances are not treated as equal; the relevant tests should pass afterward.

Written by the indexing model from the issue text.

Description

Describe the bug

I'm using @tanstack/react-form, but traced the issue back to the store here. Specifically, I'm trying to store Temporal.Duration values, but store updates are not being received via useStore because shallow returns true when both objects have no keys, i.e. Object.keys(objA) return [], instead of comparing referential equality at that point.

Steps to Reproduce the Bug or Issue

This, and any object factory that use getters instead of static properties return true.

shallow(Temporal.Duration.from({ hours: 1 }), Temporal.Duration.from({ days: 2 }));
Expected behavior

Expect to see false, since they are different values, different objects.

Screenshots or Videos

No response

Platform
  • OS: macOS
  • Browser: Arc (Chromium)
  • Version: 138.0
Additional context

No response

Dominant language
TypeScript
Stars
893
Forks
114
Avg merge
8d 14h
Merged PRs (30d)
3

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