SetNapiModuleCreator

SetNapiModuleCreator is a C++ template method used to register a "Creator". This creator is a callable object (like a function or lambda) responsible for creating and binding your custom native module's methods within the JavaScript environment.

This API is a C++ interface, leveraging templates and C++11 features to provide enhanced type safety and flexibility. It automatically deduces your module type and ensures it correctly inherits from LynxExtensionModule.

Method Signature

template <typename Creator>
void SetNapiModuleCreator(Creator&& creator);

Parameters

Name	Type	Description	Required
`creator`	`Creator`	A callable object (function, function pointer, or lambda) used to create the N-API module. Lynx calls this during runtime initialization to expose C++ functions to JavaScript. This creator must adhere to a specific function signature, as described below.	Yes

`Creator` Signature

Your creator function must have the following signature:

Napi::Value YourCreatorFunction(Napi::Env env,
                                Napi::Value exports,
                                const char* module_name,
                                YourModuleType& module);

env: The Napi::Env environment handle, which is the context for interacting with the JavaScript engine.
exports: A Napi::Value representing a JavaScript object that you should populate with your module's native functions and properties.
module_name: The name of the module.
module: A reference to your custom module instance. YourModuleType must be a class that inherits from lynx::pub::LynxExtensionModule. The API enforces this constraint internally with a static_assert.
Return Value: You must return the exports object after populating it.

Usage

Call this method only after SetCModule, because registration immediately accesses the associated C module. The host integration should perform both calls after creating the C module and before returning it to Lynx.

Code Example

The following example demonstrates how to define a custom LynxExtensionModule and use SetNapiModuleCreator to expose a native method to JavaScript.

#include "lynx/platform/embedder/public/lynx_extension_module.h"

// 1. Define your extension module class, inheriting from LynxExtensionModule
class MyExtensionModule : public lynx::pub::LynxExtensionModule {
public:
    MyExtensionModule() {
    }

    void OnRuntimeInit() override {
        // You can perform runtime initialization logic here
    }

    // Your custom C++ method
    std::string getGreeting() {
        return "Hello from C++!";
    }

    // 2. Define the module creator (Creator) function
    // It can be a static member function, a standalone function, or a lambda
    static Napi::Value BindMethods(Napi::Env env,
                                   Napi::Value exports,
                                   const char* module_name,
                                   MyExtensionModule& module) {
        // Use the incoming exports object
        auto exports_obj = exports.As<Napi::Object>();

        // 3. Bind your C++ method to the exports object
        exports_obj.Set("getGreeting",
                        Napi::Function::New(env, [&module](const Napi::CallbackInfo& info) {
                            Napi::Env env = info.Env();
                            // Call the method on the module instance
                            std::string message = module.getGreeting();
                            return Napi::String::New(env, message);
                        }));

        return exports_obj;
    }
};

// In your integration code, create MyExtensionModule instance and register Napi Module Creator.
LYNX_EXTERN_C lynx_extension_module_t*
demo_extension_module_create_extension_module(void* opaque) {
  auto* module = new MyExtensionModule();
  lynx_extension_module_t* c_module =
      lynx_extension_module_create_with_finalizer(
          module, [](lynx_extension_module_t* m, void* user_data) {
            if (user_data) {
              delete reinterpret_cast<MyExtensionModule*>(
                  user_data);
            }
          });
  module->SetCModule(c_module);
  module->SetNapiModuleCreator(&MyExtensionModule::BindMethods);
  return c_module;
}

Compatibility

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#SetNapiModuleCreator

#Method Signature

#Parameters

#Creator Signature

#Usage

#Code Example

#See Also

#Compatibility