Who contributed to Meta on August 19, 2026?

6 developers shipped this update, including Christian Falch, nishan (o^▽^o), Pieter De Baets, Riccardo Cipolleschi, SimenB, and ahnpnl.

What were the notable Meta updates?

perf(jest-resolve): cut repeated work on the resolution hot path, fix(jest-resolve): repair the `shouldLoadAsEsm` lookup caches, and fix(jest-runtime): mirror Node's ESM/CJS interop and entry-point metadata.

Jest's resolver gets a major speedup and Node-compatible module handling

By RepoJournal · Filed 06:58 UTC on August 19, 2026 · About Meta

6 people shipped this

SimenB @SimenB 4 cited

Pieter De Baets @javache 2 cited

Christian Falch @chrfalch 1 cited

nishan (o^▽^o) @intergalacticspacehighway 1 cited

Riccardo Cipolleschi @cipolleschi 1 cited

ahnpnl @ahnpnl 1 cited

SimenB's latest PRs cut repeated work on the resolution hot path and fix several long-standing module system bugs, making Jest faster and more accurate than ever.

Jest's resolver hot path just got leaner [1], cutting repeated work on every resolution, and the shouldLoadAsEsm lookup caches are fixed [2] after a bug that survived since v16. Jest's runtime now mirrors Node's ESM/CJS interop [3] and throws ERR_REQUIRE_CYCLE_MODULE on require(esm) re-entry [4], closing a double-execution gap. CustomConsole now buffers output [5], so reporters finally get console data in verbose mode. Meanwhile, React Native graduates three style props [6] and removes the Android font weight flag [7], simplifying the API. A SwiftPM fix [8] addresses array build settings, a subtle but real bug for iOS projects. CI moves to macOS 26 runners [9], and ref callbacks now return void explicitly [10], matching React's contract. The period saw 24 commits and 10 PRs across two repos, with SimenB dominating Jest's improvements.

Action items

→ Test your Jest setup with the latest resolver and runtime fixes to catch any behavior changes facebook/jest [plan]
→ Upgrade React Native to include the SwiftPM fix if you use array build settings facebook/react-native [plan]
→ Monitor the style prop graduation to update any experimental_ usage facebook/react-native [monitor]

References

[1] perf(jest-resolve): cut repeated work on the resolution hot path ↗ facebook/jest
[2] fix(jest-resolve): repair the `shouldLoadAsEsm` lookup caches ↗ facebook/jest
[3] fix(jest-runtime): mirror Node's ESM/CJS interop and entry-point metadata ↗ facebook/jest
[4] fix(jest-runtime): throw ERR_REQUIRE_CYCLE_MODULE on require(esm) re-entry ↗ facebook/jest
[5] fix(jest-console): buffer console output in CustomConsole for reporters ↗ facebook/jest
[6] feat(style): remove `experimental_` prefix from `backgroundSize`, `backgroundPosition` and `backgroundRepeat` (#57563) facebook/react-native
[7] Remove enableAndroidFontWeightAdjustment feature flag (#57990) facebook/react-native
[8] fix(swiftpm): fix two ways array build settings were mishandled (#57744) facebook/react-native
[9] Use macOS 26 runners for iOS E2E tests (#57993) facebook/react-native
[10] Remove accidental ref callback return values (#57849) facebook/react-native

Quick answers

What shipped in Meta on August 19, 2026?: SimenB's latest PRs cut repeated work on the resolution hot path and fix several long-standing module system bugs, making Jest faster and more accurate than ever. In total, 24 commits and 10 pull requests landed.
Who contributed to Meta on August 19, 2026?: 6 developers shipped this update, including Christian Falch, nishan (o^▽^o), Pieter De Baets, Riccardo Cipolleschi, SimenB, and ahnpnl.
What were the notable Meta updates?: perf(jest-resolve): cut repeated work on the resolution hot path, fix(jest-resolve): repair the `shouldLoadAsEsm` lookup caches, and fix(jest-runtime): mirror Node's ESM/CJS interop and entry-point metadata.

React Fragments leak listeners as refs re-attach

A subtle React bug is piling up event listeners when Fragment refs re-attach with a fresh identity on each render.

javascript 20 shipped

Meta Aug 18

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 17

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

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

javascript 30 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

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