How to Add Custom JSI Bindings in Your TurboModule (and Why You Might Need Them)

React Native's TurboModules cover most native integration needs, but JSI (JavaScript Interface) is the lower-level escape hatch for edge cases. A practical example shows how to implement the RCTTurboModuleWithJSIBindings protocol to inject custom global functions into the JS runtime, specifically to pass ArrayBuffer data from JavaScript to native code without serialization overhead. The step-by-step guide covers defining a host function via a C++ lambda, validating and accessing raw ArrayBuffer data with zero-copy, and registering the function globally. The post also notes that first-class ArrayBuffer support is coming to TurboModules directly.