feat: Pass View callbacks to native directly on react-native 0.81+

[mrousavy]

Function props no longer need the { f: … } object workaround on react-native 0.81 and above.

Why this works now

react-native converts every function prop to true before it reaches native - unless the View Config declares a process function for that prop. That escape hatch landed in facebook/react#32119 / facebook/react-native#48777 and first shipped in react-native 0.81.0 (verified against the published packages: attributeConfigHasProcess is absent in 0.80.3, present in 0.81.0-rc.0):

// ReactNativeAttributePayload.js (react-native 0.81+)
if (typeof nextProp === 'function') {
  const attributeConfigHasProcess =
    typeof attributeConfig === 'object' &&
    typeof attributeConfig.process === 'function'
  if (!attributeConfigHasProcess) { nextProp = true; … }
}

Nitro already sets process: (i) => i on every attribute in wrapValidAttributes(...) (added in #853 for the custom diff), so on 0.81+ functions already arrive as raw jsi::Functions - the wrapper was just dead weight.

What changed

-<Camera onCaptured={callback((i) => console.log(i))} />
+<Camera onCaptured={(i) => console.log(i)} />

Both react-native versions keep a fast path - the version is resolved once, never per prop:

• C++: a compile-time #if on REACT_NATIVE_VERSION_* (NITRO_RAW_FUNCTION_PROPS in RawPropsCompat.hpp). On 0.81+ the function-prop branch in CachedProp::fromRawValue(...) compiles away entirely and functions go straight into JSIConverter; on 0.78 - 0.80 the { f: … } object is unwrapped exactly as before.
• JS: callback(...) reads Platform.constants.reactNativeVersion once, memoizes it, and returns the function as-is on 0.81+.

callback(...) is now @deprecated but still works everywhere, and View props accept both a raw function and a wrapped { f: … } object, so this is not a breaking change for apps on react-native 0.78 - 0.80 or for existing callback(...) call sites.

Also fixes a latent crash on react-native 0.78 - 0.80: react-native puts an explicit null in the props payload for a removed prop, which used to throw in value.asObject(...) while unwrapping f (e.g. when hybridRef goes from set to undefined).

Tests

• Migrated the View harness tests to raw functions, so the whole existing View suite now covers the new path.
• "still accepts callbacks wrapped in the deprecated callback(...)" - back-compat coverage for the wrapper.
• "keeps updating props after an optional callback prop is removed" - regression test for the null case above.
• Compile-checked CachedProp.hpp against react-native 0.85 headers with NITRO_RAW_FUNCTION_PROPS both 1 and 0.

Docs

"Callbacks have to be wrapped" is now "Callbacks", documenting raw functions as the default and callback(...) as the react-native 0.78 - 0.80 workaround.

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Project	Deployment	Actions	Updated (UTC)
nitro-docs	Ready	Preview	Aug 20, 2026 2:12pm

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[chatgpt-codex-connector]

Unwrap legacy callback objects on RN 0.81+

On React Native 0.81+, this unconditional raw-value path sends a legacy { f: function } wrapper into JSIConverter<std::function<...>>, whose fromJSI tries to cast the object itself to a function and throws. This conflicts with the newly exported AllowWrappedFunctions type, which explicitly accepts the wrapper, and breaks older JS bundles or callers constructing the public wrapper format after the native app is upgraded. The added compatibility test does not exercise this case on RN 0.81+ because the updated callback(...) helper returns the raw function there; this path should preserve raw functions while still detecting and unwrapping { f: ... } objects.

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