Refactoring day1

node_modules/node-addon-api/doc/bigint.md

@@ -79,7 +79,7 @@ Returns the number of words needed to store this `BigInt` value.
 ### ToWords
 
 ```cpp
-void Napi::BigInt::ToWords(size_t* word_count, int* sign_bit, uint64_t* words);
+void Napi::BigInt::ToWords(int* sign_bit, size_t* word_count, uint64_t* words);
 ```
 
  - `[out] sign_bit`: Integer representing if the JavaScript `BigInt` is positive

node_modules/node-addon-api/doc/env.md

@@ -75,3 +75,58 @@ The `script` can be any of the following types:
 - [`Napi::String`](string.md)
 - `const char *`
 - `const std::string &`
+
+### GetInstanceData
+```cpp
+template <typename T> T* GetInstanceData();
+```
+
+Returns the instance data that was previously associated with the environment,
+or `nullptr` if none was associated.
+
+### SetInstanceData
+
+```cpp
+template <typename T> using Finalizer = void (*)(Env, T*);
+template <typename T, Finalizer<T> fini = Env::DefaultFini<T>>
+void SetInstanceData(T* data);
+```
+
+- `[template] fini`: A function to call when the instance data is to be deleted.
+Accepts a function of the form `void CleanupData(Napi::Env env, T* data)`. If
+not given, the default finalizer will be used, which simply uses the `delete`
+operator to destroy `T*` when the addon instance is unloaded.
+- `[in] data`: A pointer to data that will be associated with the instance of
+the addon for the duration of its lifecycle.
+
+Associates a data item stored at `T* data` with the current instance of the
+addon. The item will be passed to the function `fini` which gets called when an
+instance of the addon is unloaded.
+
+### SetInstanceData
+
+```cpp
+template <typename DataType, typename HintType>
+using FinalizerWithHint = void (*)(Env, DataType*, HintType*);
+template <typename DataType,
+          typename HintType,
+          FinalizerWithHint<DataType, HintType> fini =
+            Env::DefaultFiniWithHint<DataType, HintType>>
+void SetInstanceData(DataType* data, HintType* hint);
+```
+
+- `[template] fini`: A function to call when the instance data is to be deleted.
+Accepts a function of the form
+`void CleanupData(Napi::Env env, DataType* data, HintType* hint)`. If not given,
+the default finalizer will be used, which simply uses the `delete` operator to
+destroy `T*` when the addon instance is unloaded.
+- `[in] data`: A pointer to data that will be associated with the instance of
+the addon for the duration of its lifecycle.
+- `[in] hint`: A pointer to data that will be associated with the instance of
+the addon for the duration of its lifecycle and will be passed as a hint to
+`fini` when the addon instance is unloaded.
+
+Associates a data item stored at `T* data` with the current instance of the
+addon. The item will be passed to the function `fini` which gets called when an
+instance of the addon is unloaded. This overload accepts an additional hint to
+be passed to `fini`.

node_modules/node-addon-api/doc/object_wrap.md

@@ -22,49 +22,57 @@ your C++ class methods.
 class Example : public Napi::ObjectWrap<Example> {
   public:
     static Napi::Object Init(Napi::Env env, Napi::Object exports);
-    Example(const Napi::CallbackInfo &info);
+    Example(const Napi::CallbackInfo& info);
+    static Napi::Value CreateNewItem(const Napi::CallbackInfo& info);
 
   private:
-    static Napi::FunctionReference constructor;
     double _value;
-    Napi::Value GetValue(const Napi::CallbackInfo &info);
-    Napi::Value SetValue(const Napi::CallbackInfo &info);
+    Napi::Value GetValue(const Napi::CallbackInfo& info);
+    Napi::Value SetValue(const Napi::CallbackInfo& info);
 };
 
 Napi::Object Example::Init(Napi::Env env, Napi::Object exports) {
     // This method is used to hook the accessor and method callbacks
     Napi::Function func = DefineClass(env, "Example", {
         InstanceMethod<&Example::GetValue>("GetValue"),
-        InstanceMethod<&Example::SetValue>("SetValue")
+        InstanceMethod<&Example::SetValue>("SetValue"),
+        StaticMethod<&Example::CreateNewItem>("CreateNewItem"),
     });
 
+    Napi::FunctionReference* constructor = new Napi::FunctionReference();
+
     // Create a peristent reference to the class constructor. This will allow
     // a function called on a class prototype and a function
     // called on instance of a class to be distinguished from each other.
-    constructor = Napi::Persistent(func);
-    // Call the SuppressDestruct() method on the static data prevent the calling
-    // to this destructor to reset the reference when the environment is no longer
-    // available.
-    constructor.SuppressDestruct();
+    *constructor = Napi::Persistent(func);
     exports.Set("Example", func);
+
+    // Store the constructor as the add-on instance data. This will allow this
+    // add-on to support multiple instances of itself running on multiple worker
+    // threads, as well as multiple instances of itself running in different
+    // contexts on the same thread.
+    //
+    // By default, the value set on the environment here will be destroyed when
+    // the add-on is unloaded using the `delete` operator, but it is also
+    // possible to supply a custom deleter.
+    env.SetInstanceData<Napi::FunctionReference>(constructor);
+
     return exports;
 }
 
-Example::Example(const Napi::CallbackInfo &info) : Napi::ObjectWrap<Example>(info) {
+Example::Example(const Napi::CallbackInfo& info) : Napi::ObjectWrap<Example>(info) {
     Napi::Env env = info.Env();
     // ...
     Napi::Number value = info[0].As<Napi::Number>();
     this->_value = value.DoubleValue();
 }
 
-Napi::FunctionReference Example::constructor;
-
-Napi::Value Example::GetValue(const Napi::CallbackInfo &info){
+Napi::Value Example::GetValue(const Napi::CallbackInfo& info){
     Napi::Env env = info.Env();
     return Napi::Number::New(env, this->_value);
 }
 
-Napi::Value Example::SetValue(const Napi::CallbackInfo &info){
+Napi::Value Example::SetValue(const Napi::CallbackInfo& info){
     Napi::Env env = info.Env();
     // ...
     Napi::Number value = info[0].As<Napi::Number>();
@@ -78,6 +86,16 @@ Napi::Object Init (Napi::Env env, Napi::Object exports) {
     return exports;
 }
 
+// Create a new item using the constructor stored during Init.
+Napi::Value Example::CreateNewItem(const Napi::CallbackInfo& info) {
+  // Retrieve the instance data we stored during `Init()`. We only stored the
+  // constructor there, so we retrieve it here to create a new instance of the
+  // JS class the constructor represents.
+  Napi::FunctionReference* constructor =
+      info.Env().GetInstanceData<Napi::FunctionReference>();
+  return constructor->New({ Napi::Number::New(info.Env(), 42) });
+}
+
 // Register and initialize native add-on
 NODE_API_MODULE(NODE_GYP_MODULE_NAME, Init)
 ```
@@ -137,7 +155,7 @@ static T* Napi::ObjectWrap::Unwrap(Napi::Object wrapper);
 
 * `[in] wrapper`: The JavaScript object that wraps the native instance.
 
-Returns a native instace wrapped in a JavaScript object. Given the
+Returns a native instance wrapped in a JavaScript object. Given the
 Napi:Object, this allows a method to get a pointer to the wrapped
 C++ object and then reference fields, call methods, etc. within that class.
 In many cases calling Unwrap is not required, as methods can