upgrade ObjectWrap example to multi-context support

Author: anfilat

6_object_wrap/node-addon-api/addon.js

@@ -1,13 +1,42 @@
-var addon = require('bindings')('addon');
+const addon = require('bindings')('addon');
+const {Worker, isMainThread, workerData} = require('worker_threads');
+const os = require('os');
 
-var obj = new addon.MyObject(10);
-console.log( obj.plusOne() ); // 11
-console.log( obj.plusOne() ); // 12
-console.log( obj.plusOne() ); // 13
+if (isMainThread) {
+    (async function main() {
+        const threads = new Promise(resolve => {
+            const size = os.cpus().length * 2;
+            let wait = size;
 
-console.log( obj.multiply().value() ); // 13
-console.log( obj.multiply(10).value() ); // 130
+            for (let i = 0; i < size; i++) {
+                const worker = new Worker(__filename, {workerData: i});
 
-var newobj = obj.multiply(-1);
-console.log( newobj.value() ); // -13
-console.log( obj === newobj ); // false
+                worker.on('exit', () => {
+                    wait--;
+                    if (wait === 0) {
+                        resolve();
+                    }
+                });
+            }
+        });
+
+        work('main');
+        await threads;
+    })();
+} else {
+    work(workerData);
+}
+
+function work(id) {
+    const obj = new addon.MyObject(10);
+    for (let i = 0; i < 10; i++) {
+        console.log(id, obj.plusOne());
+    }
+
+    console.log(id, obj.multiply().value());
+    console.log(id, obj.multiply(10).value());
+
+    const newobj = obj.multiply(-1);
+    console.log(id, newobj.value());
+    console.log(id, obj === newobj);
+}

6_object_wrap/node-addon-api/myobject.cc

@@ -1,6 +1,14 @@
 #include "myobject.h"
 
-Napi::FunctionReference MyObject::constructor;
+class AddonData {
+public:
+  AddonData(Napi::Function func) {
+    MyObjectConstructor = Napi::Persistent(func);
+    MyObjectConstructor.SuppressDestruct();
+  }
+
+  Napi::FunctionReference MyObjectConstructor;
+};
 
 Napi::Object MyObject::Init(Napi::Env env, Napi::Object exports) {
   Napi::HandleScope scope(env);
@@ -12,8 +20,7 @@ Napi::Object MyObject::Init(Napi::Env env, Napi::Object exports) {
                    InstanceMethod("value", &MyObject::GetValue),
                    InstanceMethod("multiply", &MyObject::Multiply)});
 
-  constructor = Napi::Persistent(func);
-  constructor.SuppressDestruct();
+  env.SetInstanceData(new AddonData(func));
 
   exports.Set("MyObject", func);
   return exports;
@@ -55,7 +62,7 @@ Napi::Value MyObject::Multiply(const Napi::CallbackInfo& info) {
     multiple = info[0].As<Napi::Number>();
   }
 
-  Napi::Object obj = constructor.New(
+  Napi::Object obj = info.Env().GetInstanceData<AddonData>()->MyObjectConstructor.New(
       {Napi::Number::New(info.Env(), this->value_ * multiple.DoubleValue())});
 
   return obj;

6_object_wrap/node-addon-api/myobject.h

@@ -9,8 +9,6 @@ class MyObject : public Napi::ObjectWrap<MyObject> {
   MyObject(const Napi::CallbackInfo& info);
 
  private:
-  static Napi::FunctionReference constructor;
-
   Napi::Value GetValue(const Napi::CallbackInfo& info);
   Napi::Value PlusOne(const Napi::CallbackInfo& info);
   Napi::Value Multiply(const Napi::CallbackInfo& info);

6_object_wrap/node-addon-api/package.json

@@ -7,6 +7,6 @@
   "gypfile": true,
   "dependencies": {
     "bindings": "~1.2.1",
-    "node-addon-api": "^1.0.0"
+    "node-addon-api": "^3.0.0"
   }
 }