Writing Node.js Plugins (4) - Implementation of Function Factory and Object Factory

In this article, we complete examples of function factories and object factories through nodejs plugins.

First look at the following node.js code, the my_node_addon plugin we reference needs to be exported

createFunc function and createObject function, and the object returned by the createObject function contains 

add and addCallback two addition functions

var addon = require('bindings')('my_node_addon.node');

//函数工厂
var func=addon.createFunc()(1);
console.log('Create  Function ret:' ,func);

//对象工厂
var obj = addon.createObject();
//调用对象方法
console.log(obj.add(3, 12))
//调用对象的额回调方法
obj.addCallback(1, 2, (ret) => {
    console.log(ret);
});

The plug-in source code main.cpp is as follows 

#include <napi.h>

/**
 * 加法
 * @param info
 * @return
 */
Napi::Value Add(const Napi::CallbackInfo &info) {
    //获取上下文环境
    Napi::Env env = info.Env();
    //如果参数少于2
    if (info.Length() < 2) {
        //js中丢出类型异常
        Napi::TypeError::New(env, "Wrong number of argumen