What does Javascript's easy-to-ignore little knowledge Point new do?

Problem: usually we often write var ss = New Person (); SS is an object generated by the ' person class ', but our person method does not write return;

(var ss= person (); returns undefined because no return is written in the METHOD)

Let's start with a regular code.

function person (name) {        this. name= name;         returnthis;    };     function () {        returnthis. name;    };     var ss= New Person (a);    Console.log (ss);

The people of the Earth know that the print results are

And then the second situation

var New  function person (name) {        this. name = name;          return this ;    };     function () {        returnthis. name;    };     var ss= person.apply (obj);    Console.log (ss);

Printing results are

You might also think it's normal, so let's see

var New  function person (name) {        this. name = name;         // return this;     };     function () {        returnthis. name;    };     var ss= person.apply (obj);    Console.log (ss);

The print result is--undefined

From this we can draw the conclusion that:

1 JavaScript does not have the concept of class, it is important to remember, do not be affected by other class-based language (such as java), that the object must be created by the class, the function is a kind of object

2 New keyword We can think of doing the following several things

 var  ss = (function   var  obj = new  obj ECT (); // new an object--only to find that new is used here ... How does this explain ...? I still have a study on wood.  obj.__proto__ = person.prototype; //         The prototype of the object points to the Person's prototype  var  ret = constructor.apply (obj, arguments); //        this--point to obj  return  typeof  ret = = = ' Object '? ret:obj; //  }) (person)  

Supplementary: the object literal cannot be directly found in its own prototype, it must be delegated to its constructor, and then the constructor will find its prototype

What does Javascript's easy-to-ignore little knowledge Point new do?