另一种常见情况是创建 JavaScript 函数来包装 C++ 函数，并返回到 JavaScript：

    1. // addon.cc
    2. #include <node.h>
    4. namespace demo {
    6. using v8::Context;
    7. using v8::Function;
    8. using v8::FunctionCallbackInfo;
    9. using v8::FunctionTemplate;
    10. using v8::Isolate;
    11. using v8::Local;
    12. using v8::Object;
    13. using v8::String;
    14. using v8::Value;
    16. void MyFunction(const FunctionCallbackInfo<Value>& args) {
    17.   Isolate* isolate = args.GetIsolate();
    18.   args.GetReturnValue().Set(String::NewFromUtf8(
    19.       isolate, "hello world").ToLocalChecked());
    20. }
    22. void CreateFunction(const FunctionCallbackInfo<Value>& args) {
    23.   Isolate* isolate = args.GetIsolate();
    25.   Local<Context> context = isolate->GetCurrentContext();
    26.   Local<FunctionTemplate> tpl = FunctionTemplate::New(isolate, MyFunction);
    27.   Local<Function> fn = tpl->GetFunction(context).ToLocalChecked();
    29.   // 可以省略这步使它匿名
    30.   fn->SetName(String::NewFromUtf8(
    31.       isolate, "theFunction").ToLocalChecked());
    33.   args.GetReturnValue().Set(fn);
    34. }
    36. void Init(Local<Object> exports, Local<Object> module) {
    37.   NODE_SET_METHOD(module, "exports", CreateFunction);
    38. }
    40. NODE_MODULE(NODE_GYP_MODULE_NAME, Init)
    42. }  // namespace demo

    测试它：

    1. // test.js
    2. const addon = require('./build/Release/addon');
    4. const fn = addon();
    5. console.log(fn());
    6. // 打印: 'hello world'