Defining objects in javascript factory mode_Basic knowledge

Each function object has a length attribute, indicating the number of parameters the function expects to receive.

Copy code The code is as follows: var add =function(num1,num2,num3){ alert(num1 num2 num3); } alert(add.length); About the object-oriented creation method of js,

Target:

Construct an order object. Contains three attributes: date, amount, submitter Contains a method: display string: "XX submitted an order with an amount of XXXX yuan at XXXX-XX-XX"

1 Factory method

Copy code The code is as follows: /* Factory method: Return objects by using methods. There is no need to generate new objects through new when using them. */ function createOrder()//You can also build a factory method with parameters and initialize the object data according to the parameters passed in. { var order = new Object(); Order.Date = "1990-1-1"; Order.Price = "3200"; Order.Name = "Vince Keny"; order.Show = function()//Put the show method in the factory and create a Show method for each instance. Waste of resources is the drawback of this model. alert(this.Name " submitted an order with a limit of " this.Price " yuan on " this.Date ".") return order; } //Use factory mode to return objects: var order = createOrder(); // You can also use it this way, changing the factory pattern into a "pseudo constructor". Because new is used in the factory, the new operator when creating an object will be ignored. var order2 = new createOrder(); Order.Show(); Order2.Show();

2 Constructor method

Copy code The code is as follows: /* In the constructor method, method declaration is the same as the factory method, and there are the same problems, which can also be extracted. The difference is that when declaring attributes, use this And you need to use the new operator to generate an instance. */ function Order() { This.Date = "1990-1-1"; This.Price = "3200"; This.Name = "Vince Keny"; This.Show = function() { alert(this.Name " submitted an order with the amount of " this.Price " yuan on " this.Date ".") } }

var order = new Order(); order.Show(); Three prototype methods

Copy code The code is as follows: /* Prototype method: use prototype */ function Order() {}

Order.prototype.Date = "1990-1-1"; Order.prototype.Price = "3200"; Order.prototype.Name = "Vince Keny"; Order.prototype.Show = function() { alert(this.Name " submitted an order with the amount of " this.Price " yuan on " this.Date ".") } var order = new Order(); order.Show(); Four mixed constructor/prototype methods

Copy code The code is as follows: /* Mixed constructor/prototype method: Use the constructor method to initialize attribute fields, and use the prototype method to construct methods. */ function Order() { This.Date = "1990-1-1"; This.Price = "3200"; This.Name = "Vince Keny"; } Order.prototype.Show = function(). { alert(this.Name " submitted an order with the amount of " this.Price " yuan on " this.Date ".") } var order = new Order(); order.Show(); Five Dynamic Mixing Methods

Copy code The code is as follows: /* Dynamic hybrid method: The difference from the hybrid method is the position where the method is declared. The method life is placed inside the constructor, which is more in line with object-oriented. */ function Order() { This.Date = "1990-1-1"; This.Price = "3200"; This.Name = "Vince Keny"; If(typeof Order._initialized == "undefined") { Order.prototype.Show = function(). alert(this.Name " submitted an order with a limit of " this.Price " yuan on " this.Date ".") }; Order._initialized = true; } }

function Car(sColor,iDoors){ var oTempCar = new Object; oTempCar.color = sColor; oTempCar.doors = iDooes; oTempCar.showColor = function (){ alert(this.color) }; return oTempCar; } var oCar1 = new Car("red",4); var oCar2 = new Car("blue",3); oCar1.showColor(); //outputs "red" oCar2.showColor(); //outputs "blue"