打印一个js对象的实际类型

Question

http.createServer((req,res)=>{
    res.write('hello world');
    console.log(typeof res);// obj
    res.end();
});

如何 查看req和res的具体对象类型，这样可以去文档中看具体详细api.typeof打印出的是object，我希望打印出的是http.ServerResponse

怎么搞

Answer 1

打印函数的类信息:

function classof(obj){
    if(typeof(obj)==="undefined")return "undefined";
    if(obj===null)return "Null";
    var res = Object.prototype.toString.call(obj).match(/^\[object\s(.*)\]$/)[1];
    if(res==="Object"){
        res = obj.constructor.name;
        if(typeof(res)!='string' || res.length==0){
            if(obj instanceof jQuery)return "jQuery";// jQuery build stranges Objects
            if(obj instanceof Array)return "Array";// Array prototype is very sneaky
            return "Object";
        }
    }
    return res;
}

// Example
console.log(classof(new Date()));   // => "Date"