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PerformanceObserver accepts invalid callbacks until delivery

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#58,238 1 comment 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
55/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
javascript, react-native
Domain
api, mobile-dev

Research direction

Trace the PerformanceObserver constructor and the native delivery path to find where the callback is stored and later invoked. Add coverage for a missing callback and explicitly supplied non-functions, then verify construction throws synchronously with the expected errors and that valid callbacks still work.

Written by the indexing model from the issue text.

Description

Needs: Author Feedback Needs: Repro
Description

PerformanceObserver stores its constructor argument without validating that one was supplied or that it is callable. Missing, null, and other non-function callbacks therefore create invalid observer instances and fail only later when native delivery attempts to invoke the value.

Expected behavior

Construction without the required argument should throw synchronously, and an explicitly supplied non-function should throw the corresponding callback type error, matching the PerformanceObserver API contract.

React Native Version

0.87.1 and current main

Affected Platforms

New Architecture - All

Dominant language
C++
Stars
127k
Forks
25.3k
PR merge metrics
No merged PRs in 30d

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  4. Open a pull request that references the issue number.

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