Creating several advantages and disadvantages between JavaScript objects

JavaScript common objects are several ways to create: Object constructor, object literal pattern, plant pattern, custom constructor mode, plus prototype constructor combination mode; they each have their own advantages and disadvantages and usage scenarios.

1. Object Model constructor

• Usage scenarios: initial uncertain data within the object.
• Cons: Too many statements

     var p = new Object()
        p.name = 'tom'
        p.age = 12
        p.steName = function (name) {
            this.name = name
        }

2. The object literal mode

• Application scenarios: object data determined at the start.
• Cons: If you create multiple objects, duplicate code.

var p = {
            name: 'jack',
            age: 13,
            setName: function (name) {
                this.name = name
            }
        }

3. Factory Pattern

• Application scenario: the need to create multiple objects.
• Cons: object does not have a specific type of Object type.

function createPerson (name,age) { //返回一个对象的函数就是工厂函数
            var obj = {
                name: name,
                age: age,
                sstName: function (name) {
                    this.name = name
                }
            }
            return obj
        }

4. Custom Model constructor

• Usage scenarios: the need to create multiple types of objects identified.
• Disadvantages: Each object has the same data (method), a waste of memory.

function Person (name,age) {
            this.name = name
            this.age = age
            this.setName = function (name) {
                this.name = name
            }
        }
        var p1 = new Person('tom',15)
        var p2 = new Person('jack',14)
        console.log(p1 instanceof Person) //true p1是Person类型

        function student (name,grade) {
            this.name = name
            this.grade = grade
        }  

        var s1 = new student('peter',6)
        console.log(s1 instanceof student) //true s1是student类型

        console.log(p1,p2)

p1 and p2 have each have the same setName () method, resulting in a waste of memory.

The prototype model constructor +

• Usage scenarios: To create multiple types of objects identified

function Person (name,age) {
           this.name  = name
           this.age = age
       }
       Person.prototype.setName = function (name) {
           this.name = name
       }

       var p1 = new Person('tom',12)
       var p2 = new Person('jack',13)

       console.log(p1,p2)

Method of the object is placed on top of the prototype avoiding wasted memory.