568244232e
## Summary Set up the experiment to migrate event dispatching in the React Native renderer to be based on the native EventTarget API. Behind the `enableNativeEventTargetEventDispatching` flag, events are dispatched through `dispatchTrustedEvent` instead of the legacy plugin system. Regular event handler props are NOT registered via addEventListener at commit time. Instead, a hook on EventTarget (`EVENT_TARGET_GET_DECLARATIVE_LISTENER_KEY`) extracts handlers from `canonical.currentProps` at dispatch time, shifting cost from every render to only when events fire. The hook is overridden in ReactNativeElement to look up the prop name via a reverse mapping from event names (built lazily from the view config registry). Responder events bypass EventTarget entirely. `negotiateResponder` walks the fiber tree directly (capture then bubble phase), calling handlers from `canonical.currentProps` and checking return values inline. Lifecycle events (`responderGrant`, `responderMove`, etc.) call handlers directly from props and inspect return values — `onResponderGrant` returning `true` blocks native responder, `onResponderTerminationRequest` returning `false` refuses termination. This eliminates all commit-time cost for responder events (no wrappers, no addEventListener, no `responderWrappers` on canonical). ## How did you test this change? Flow Tested e2e in RN using Fantom tests (that will land after this).
24 lines
934 B
JavaScript
24 lines
934 B
JavaScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow
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*/
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// These globals are set by React Native (e.g. in setUpDOM.js, setUpTimers.js)
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// and provide access to RN's feature flags. We use global functions because we
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// don't have another mechanism to pass feature flags from RN to React in OSS.
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// Values are lazily evaluated and cached on first access.
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let _enableNativeEventTargetEventDispatching: boolean | null = null;
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export function enableNativeEventTargetEventDispatching(): boolean {
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if (_enableNativeEventTargetEventDispatching == null) {
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_enableNativeEventTargetEventDispatching =
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typeof RN$isNativeEventTargetEventDispatchingEnabled === 'function' &&
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RN$isNativeEventTargetEventDispatchingEnabled();
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}
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return _enableNativeEventTargetEventDispatching;
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}
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