feat: add node-addon-api example for async_work_promise (#212)

* feat: add node-addon-api example for async_work_promise

Author: matthewkeil

async_work_promise/node-addon-api/addon.cc

@@ -0,0 +1,32 @@
+#include "napi.h"
+#include "worker.h"
+
+Napi::Value DoHeavyMath(const Napi::CallbackInfo& info) {
+  Napi::Env env = info.Env();
+
+  if (!info[0].IsNumber()) {
+    Napi::TypeError::New(env, "num1 must be a number")
+        .ThrowAsJavaScriptException();
+    return env.Undefined();
+  }
+  uint32_t num_1 = info[0].As<Napi::Number>().Uint32Value();
+  
+  if (!info[1].IsNumber()) {
+    Napi::TypeError::New(env, "num2 must be a number")
+        .ThrowAsJavaScriptException();
+    return env.Undefined();
+  }
+  uint32_t num_2 = info[1].As<Napi::Number>().Uint32Value();
+  
+  DoHeavyMathWorker* worker = new DoHeavyMathWorker(env, num_1, num_2);
+  worker->Queue();
+  return worker->GetPromise();
+}
+
+Napi::Object Init(Napi::Env env, Napi::Object exports) {
+  exports.Set(Napi::String::New(env, "doHeavyMath"),
+              Napi::Function::New(env, DoHeavyMath));
+  return exports;
+}
+
+NODE_API_MODULE(NODE_GYP_MODULE_NAME, Init)

async_work_promise/node-addon-api/binding.gyp

@@ -0,0 +1,32 @@
+{
+  "targets": [{
+    "target_name": "addon",
+    "sources": [
+      "addon.cc"
+    ],
+    "include_dirs": [
+      "<!@(node -p \"require('node-addon-api').include\")"
+    ],
+    'defines': [ 'NAPI_CPP_EXCEPTIONS' ],
+    'conditions': [
+      [ 'OS=="win"', {
+        'defines': [ '_HAS_EXCEPTIONS=1' ],
+        'msvs_settings': {
+          'VCCLCompilerTool': {
+            'ExceptionHandling': 1,
+          },
+        },
+      }],
+      [ 'OS=="linux"', {
+        "cflags": [ "-fexceptions" ],
+        "cflags_cc": [ "-fexceptions" ],
+      }],
+      [ 'OS=="mac"', {
+        'xcode_settings': {
+          'GCC_ENABLE_CPP_EXCEPTIONS': 'YES',
+          'CLANG_CXX_LIBRARY': 'libc++',
+        }
+      }]
+    ],
+  }]
+}

async_work_promise/node-addon-api/index.js

@@ -0,0 +1,3 @@
+const bindings = require("bindings")("addon");
+
+bindings.doHeavyMath(2, 1).then(console.log);

async_work_promise/node-addon-api/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "async_worker_promise",
+  "version": "0.0.0",
+  "description": "AsyncWorker example that returns a Promise",
+  "main": "index.js",
+  "scripts": {
+    "test": "node ."
+  },
+  "author": "Matthew Keil (matthewkeil)",
+  "gypfile": true,
+  "dependencies": {
+    "bindings": "^1.5.0",
+    "node-addon-api": "^7.0.0"
+  }
+}

async_work_promise/node-addon-api/worker.h

@@ -0,0 +1,43 @@
+#include "napi.h"
+
+class DoHeavyMathWorker : public Napi::AsyncWorker {
+ public:
+  DoHeavyMathWorker(const Napi::Env& env, uint32_t num_1, uint32_t num_2)
+      : Napi::AsyncWorker{env, "DoHeavyMathWorker"},
+        m_deferred{env},
+        m_num_1{num_1},
+        m_num_2{num_2} {}
+
+  /**
+   * GetPromise associated with _deferred for return to JS
+   */
+  Napi::Promise GetPromise() { return m_deferred.Promise(); }
+
+ protected:
+  /**
+   * Simulate heavy math work
+   */
+  void Execute() {
+    if (m_num_2 == 0) {
+      SetError("Cannot divide by zero");
+      return;
+    }
+    m_result = m_num_1 / m_num_2;
+  }
+
+  /**
+   * Resolve the promise with the result
+   */
+  void OnOK() { m_deferred.Resolve(Napi::Number::New(Env(), m_result)); }
+
+  /**
+   * Reject the promise with errors
+   */
+  void OnError(const Napi::Error& err) { m_deferred.Reject(err.Value()); }
+
+ private:
+  Napi::Promise::Deferred m_deferred;
+  uint32_t m_num_1;
+  uint32_t m_num_2;
+  uint32_t m_result;
+};