Implement Node-API runtime functions ☂️ #56

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1. kraenhansen

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   Host 🏡Our `react-native-node-api-modules` packageOur `react-native-node-api-modules` package

   on May 14, 2025
2. kraenhansen

   added the

   Feature

   issue type on May 14, 2025
3. kraenhansen

   added sub-issues on May 14, 2025

   • Implement napi_async_destroy #57
   • Implement napi_async_init #58
   • Implement napi_cancel_async_work #59
   • Implement napi_create_async_work #60
   • Implement napi_create_buffer #61
   • Implement napi_create_buffer_copy #62
   • Implement napi_create_external_buffer #63
   • Implement napi_delete_async_work #64
   • Implement napi_fatal_error #65
   • Implement napi_get_buffer_info #66
   • Implement napi_get_node_version #67
4. 8 remaining items

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5. kraenhansen

   added sub-issues on May 14, 2025

   • Implement napi_open_callback_scope #76
   • Implement napi_remove_env_cleanup_hook #77
   • Implement napi_acquire_threadsafe_function #78
   • Implement napi_call_threadsafe_function #79
   • Implement napi_create_threadsafe_function #80
   • Implement napi_get_threadsafe_function_context #81
   • Implement napi_ref_threadsafe_function #82
   • Implement napi_release_threadsafe_function #83
   • Implement napi_unref_threadsafe_function #84
   • Implement napi_add_async_cleanup_hook #85
   • Implement napi_remove_async_cleanup_hook #86
6. shirakaba commented on May 25, 2025

   

   shirakaba

   on May 25, 2025

   Last edited by shirakaba

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   Reference implementations for the Node-API runtime functions (linking to napi_create_async_work in each case):

   • Node.js, written in C++, based on v8.
   • Deno, written in Rust, based on v8.
   • Bun, written in Zig, based on JSC.
   • Ace, written in C++, based on an intermediate API implemented by Ark, JerryScript, QuickJS, and V8.
   • node-chakracore, written in C++, based on Chakra.
   • IoT.js, written in C, based on JerryScript.

   ❤️React with ❤️1Reacted by Kræn Hansen
7. shirakaba commented on May 25, 2025

   

   shirakaba

   on May 25, 2025

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   Where in the codebase are these to be implemented?
8. kraenhansen commented on May 29, 2025

   

   kraenhansen

   on May 29, 2025

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   That's a great question - somewhere in the host package for sure: packages/react-native-node-api-modules/cpp their implementation likely needs to reach in to React Native APIs - perhaps even JSI? 🤔 (If the latter is the case, we might need a weak map to lookup the jsi::Runtime based on napi_env too).

   I imagine we'll be implementing these functions, grouped by their Node-API version levels - we could

   • start with Node-API v1 (either in order of ease of implementation or importance)
   • figure out what we other (React Native) APIs we'd need access to
   • figure out how we'd get to them from a function taking just the napi_env
9. kraenhansen commented on Aug 12, 2026

   

   kraenhansen

   on Aug 12, 2026 – with Claude

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   Status sweep against next

   Adopting Hermes' first-party Node-API (#372) and implementing hermes_napi_host (#398) covered most of what this umbrella was tracking: the runtime-specific functions are now provided by Hermes' API/napi, with React Native supplying the pieces Hermes delegates to its embedder — a worker pool behind post_work/cancel_work, the runtime's CallInvoker behind post_task and work completions, and fatal_exception. The buffer functions and napi_fatal_error remain host implementations in packages/host/cpp/RuntimeNodeApi.cpp.

   Closed as completed (28) — each sub-issue has a comment pointing at what implements it:

   Area	Issues	Where it lives
   Async work	#59, #60, #64, #71	hermes_napi_async_work.cpp + post_work/cancel_work (HermesNapiHost.cpp)
   Async context & callback scopes	#57, #58, #69, #74, #76	hermes_napi_async_context.cpp
   Thread-safe functions	#78, #79, #80, #81, #82, #83, #84	hermes_napi_tsfn.cpp + post_task (HermesNapiHost.cpp)
   Cleanup hooks	#73, #77, #85, #86	hermes_napi.cpp
   Buffers	#61, #62, #63, #66, #68	RuntimeNodeApi.cpp (Buffer as Uint8Array)
   Fatal error / exception	#65, #75	RuntimeNodeApi.cpp / fatal_exception (HermesNapiHost.cpp)
   uv event loop	#72	hermes_napi.cpp — returns napi_generic_failure, no libuv loop by design

   Test coverage for the new surface: packages/node-addon-examples/tests/async, .../tests/threadsafe-function (a port of Node's test_threadsafe_function), .../tests/buffers (a port of test_buffer), and the Catch2 suite in packages/host/tests exercising the host contract on plain Linux.

   Still open (2):

   • Implement napi_get_node_version #67 napi_get_node_version — the host shim returns napi_generic_failure and shadows Hermes' working implementation in the generated injector. Policy call: drop the shim or keep the failure. Details in the issue.
   • Implement napi_module_register #70 napi_module_register — Hermes records the module, but our loader never reads it back, so the deprecated registration path still fails to load an addon. Details in the issue.

   Two caveats recorded on the closed issues rather than left implicit: Buffer fidelity versus a real Buffer is still #171 (the host's napi_is_buffer is also looser than Node's), and tsfn ref/unref are tracked but inert since React Native has no loop lifetime to model (#82, #84).

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   Generated by Claude Code