prototype: prototype object
Each function has a prototype attribute,
Every object (except null) is associated with another object when it is created,
This object is what we call the prototype, and every object "inherits" properties from the prototype.
But if the object itself overwrites the property, then the new property value will be adopted
Code display:
// 构造函数
function Person() {
}
// prototype是函数才会有的属性
Person.prototype.name = 'Kevin';
// 创建对象
var person1 = new Person();
var person2 = new Person();
// 对象会继承原型中的属性
console.log(person1.name) // Kevin
console.log(person2.name) // Kevin-
The attribute name is created in the prototype
-
No properties are defined after the object is created.
-
By reading the name, you can still get the value, which is the value of the name in the prototype
-
Therefore, the prototype itself is an object, which can be used to store the common attribute values of the instance object , or the default attributes
-
The purpose is to reduce unnecessary memory consumption
proto: Get your own prototype
The properties of every object will point to the prototype of this object.
Stored is the address of the prototype.
function Person() {
}
var person = new Person();
console.log(person.__proto__ === Person.prototype); // true
Prototype builder
Each prototype has a constructor attribute that points to the associated constructor function instance prototype points to the constructor function
function Person() {
}
console.log(Person === Person.prototype.constructor); // true 
Prototype chain
