Summary of examples of several ways to create custom objects in Javascript

Object constructor/object literal：

Put aside the design pattern, use the most basic method, which is to first call the Object constructor to create an Object, and then add attributes to the object.

var student = new Object();
     student.name = "xiao ming";
     student.age = 20;
     student.getName = function () {
         alert(this.name);
     }

Students who are familiar with JavaScript object literals can change to a better way of writing, which at least looks more concise.

 var student = {
        name: "xiao hong",
        age: 18,
        getName: function () {
            alert(this.name);
        }
    };

Disadvantages: A disadvantage of the above method is that when using the same interface to create many similar objects, a lot of duplicate code will be generated. This should be easy to understand. Functions (methods or classes) are generally used to create public methods. The above object creation process has no shadow of functions at all, so there is no reuse.

Constructor of custom type:

Constructor can be used to create objects of specific types.

  function Student(name,age) {
         this.name = name;
         this.age = age;
         this.sayName = function () {
             alert(this.name);
         }
     }
     var p3 = new Student("ming", 20);
     var p4 = new Student("hong", 18);
     alert(p3 instanceof Student); 
　　　　alert(p3.sayName==p4.sayName); //false

Disadvantages: The disadvantage of custom constructors is that each object will recreate its own method. In fact, the functions of these methods are the same (like sayName), but they are not the same (p3.sayName and p4.sayName is not equal).

The combination of constructor and prototype:

     function Student(name, age, friends) {
         this.name = name;
         this.age = age;
         this.friends = friends;
     }
     Student.prototype = {
         constructor: Student,
         sayName: function () {
             alert(this.name);
         }
     };

Summary: The combination of constructor and prototype is a widely recognized method for creating custom types. It is also the best method among the above methods.

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