Who contributed to Meta on August 17, 2026?

4 developers shipped this update, including Rob Hogan, Evan Katz, renovate, and SimenB.

What were the notable Meta updates?

fix(jest-haste-map): end the worker farm when the build aborts synchronously, fix(jest-haste-map): attach the watchman client's error listener before use, and [jest-circus, jest-jasmine2] Fix error-handler restore, `--expand` for assert diffs, and generator test context.

JEST TEARS DOWN WORKER FARMS BEFORE THEY LEAK, REACT NATIVE COMPILES PLATFORM CHECKS FASTER

By RepoJournal · Filed 07:05 UTC on August 17, 2026 · About Meta

4 people shipped this

SimenB @SimenB 4 cited

Rob Hogan @robhogan 1 cited

Evan Katz @evankatz14 1 cited

renovate @renovate 1 cited

Jest shipped three critical fixes to worker lifecycle management and snapshot handling that prevent resource leaks and test corruption.

SimenB landed a cluster of fixes across jest-haste-map that plug holes in how Jest manages its worker farm [1]. The build now properly ends the worker pool even when `processFile` throws synchronously, not just when workers reject. That's paired with a second fix that attaches watchman's error listener before use [2], preventing daemon startup failures from escaping unhandled. A third fix restores error handlers on the correct process object in jest-circus and jest-jasmine2 [3], where the ambient `process` in the VM sandbox was getting snapshotted instead of the actual parent process. On the React Native side, Rob Hogan merged a Babel plugin that inlines `Platform.OS` and `Platform.select(...)` at the front of RN's preset [4], running before ES modules lower to CommonJS so the optimizer can strip dead branches earlier in the pipeline. Evan Katz added object support to `fontVariationSettings` [5], letting developers pass OpenType axis tags as an object instead of just CSS strings. Jest also refreshed all lock files [6] via Renovate. Simon Bekkhus also fixed snapshot comparison logic [7] so hinted snapshots stay attached to their own test instead of getting reported obsolete and deleted on the next update.

Action items

→ Upgrade Jest to pick up worker farm fixes before your next test run facebook/jest [plan]
→ Update React Native to gain faster Platform inlining in builds facebook/react-native [monitor]

References

[1] fix(jest-haste-map): end the worker farm when the build aborts synchronously ↗ facebook/jest
[2] fix(jest-haste-map): attach the watchman client's error listener before use ↗ facebook/jest
[3] [jest-circus, jest-jasmine2] Fix error-handler restore, `--expand` for assert diffs, and generator test context ↗ facebook/jest
[4] Inline `Platform` within RN’s Babel preset (#57848) facebook/react-native
[5] Accept object font variation settings (#57929) facebook/react-native
[6] chore(deps): lock file maintenance ↗ facebook/jest
[7] fix: Keep hinted snapshots with their own test ↗ facebook/jest

Quick answers

What shipped in Meta on August 17, 2026?: Jest shipped three critical fixes to worker lifecycle management and snapshot handling that prevent resource leaks and test corruption. In total, 16 commits and 14 pull requests landed.
Who contributed to Meta on August 17, 2026?: 4 developers shipped this update, including Rob Hogan, Evan Katz, renovate, and SimenB.
What were the notable Meta updates?: fix(jest-haste-map): end the worker farm when the build aborts synchronously, fix(jest-haste-map): attach the watchman client's error listener before use, and [jest-circus, jest-jasmine2] Fix error-handler restore, `--expand` for assert diffs, and generator test context.

React Native kills the ArrayBuffer copy tax

React Native just made TurboModule ArrayBuffer crossing zero-copy on both iOS and Android, and the borrow contract is now enforced in Java.

javascript 15 shipped

Meta Aug 16

JEST FIXES ES MODULE RESOLVER LOADING

Jest can now load custom resolvers written as ES modules, closing a gap that forced developers back to CommonJS workarounds.

javascript 2 shipped

Meta Aug 15

REACT FLIPS PARALLEL TRANSITIONS BY DEFAULT, JEST FIXES ESM NAMESPACE COLLISIONS

Parallel transitions move from experimental to standard across React and React Native, while Jest patches critical bugs in module resolution and test serialization.

javascript 16 shipped

Meta Aug 14

REACT FIXES EVENT LISTENER BUG, JEST PATCHES CACHE CORRUPTION

React shipped a critical fix for `{once: true}` event listeners that were firing multiple times on Fragment children, while Jest plugged two separate cache and source map bugs that corrupted test output.