fix: wrap onEnd gesture handler to prevent worklets bundle-mode crash (deltaYOnGestureStart)

[nazmiaydogdu]

Summary

With react-native-reanimated v4 / react-native-worklets in bundle mode, dragging a sheet to dismiss crashes at the end of the pan gesture:

ReferenceError: Property 'deltaYOnGestureStart' doesn't exist
  at react-native-worklets/.worklets/<hash>.js (reactNativeActionsSheet_indexJs...)

Repro versions: react-native-actions-sheet 10.1.2, react-native-reanimated 4.5.0, react-native-worklets 0.10.0 (Babel plugin with bundleMode: true, strictGlobal: true).

Root cause

In bundle mode the worklets Babel plugin extracts each gesture callback into its own worklet file and serializes its closure. The pan gesture passes onEnd directly:

.onChange(event => onChange(event.absoluteX, event.absoluteY, event.translationY)) // wrapped
.runOnJS(true)
.onEnd(onEnd) // passed directly

So the extracted worklet is onEnd, whose first statement writes a mutable closure primitive:

const onEnd = () => {
  if (!gestureEnabled) return;
  deltaYOnGestureStart = 0; // write to a closure `let` shared with onChange -> crashes in the worklet
  ...
};

onChange does not crash because it is passed wrapped in an arrow function: the extracted worklet is a thin shim that just calls onChange (captured by reference), and with .runOnJS(true) that call runs on the JS thread where the closure is intact. onEnd lacks this indirection.

Fix

Wrap onEnd the same way onChange already is, so the extracted worklet is a thin shim and the closure writes happen in the real JS function:

.onEnd(() => onEnd());

One line, no behavior change: onEnd still runs on the JS thread via .runOnJS(true), identical to how onChange is handled.

Test plan

• Build a sheet with gestureEnabled and a scrollable body, on an app using reanimated 4 / worklets bundle mode.
• Drag the sheet down and release: before this change it crashes with the ReferenceError above, after it the sheet snaps/closes normally.
• Verify scroll inside the sheet, backdrop tap, and Android back button still work.

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