The internal process of new instantiation object in js

function Person () {
    
    
    this.name = name;
    this.age = age;
    this.job = job;
 
    this.sayName = function () {
    
    
        return this.name;
    };
}
 
var person = new Person("tom", 21, "WEB");
 
console.log(person.name);

Using the keyword new to create a new instance object goes through the following steps:

1. Create a new object, such as: var person = {};

2. The _proto_ property of the new object points to the prototype object prototype of the constructor.

3. Assign the scope of the constructor to the new object. (So ​​this object points to the new object)

4. Execute the code inside the constructor and add attributes to the this object in person.

5. Return the new object person.