设计模式-创建型模式-工厂模式（工厂三兄弟） TypeScript

简单工厂模式

定义一个接口，三个具体类。然后书写如下，通过选择，生产出相应的对象

// 定义Shape接口
interface Shape {
    draw():void;
}

// 下面为产品类
// 产品 Circle
class Circle implements Shape{
    public constructor(){

    }

    public draw():void{

    }
}

// 产品Rectangle
class Rectangle implements Shape{
    public constructor(){

    }
    public draw():void{

    }
}

// 下面为生产产品的工厂，根据选择，生产出不同的产品
class ShapeFactory {
    constructor(){

    }
    public static getShape(typeShape:string):Shape{
        if(typeShape === "Circle"){
            return new Circle();
        }

        if (typeShape === "Rectangle"){
            return new Rectangle();
        }

        if (typeShape === null){
            return null;
        }

        return null;
    }
}

// 下面编写测试
let test:Shape = ShapeFactory.getShape("Circle");
// 调用draw方法
test.draw();

编译后的js如下

// 下面为产品类
// 产品 Circle
var Circle = /** @class */ (function () {
    function Circle() {
    }
    Circle.prototype.draw = function () {
    };
    return Circle;
}());
// 产品Rectangle
var Rectangle = /** @class */ (function () {
    function Rectangle() {
    }
    Rectangle.prototype.draw = function () {
    };
    return Rectangle;
}());
// 下面为生产产品的工厂，根据选择，生产出不同的产品
var ShapeFactory = /** @class */ (function () {
    function ShapeFactory() {
    }
    ShapeFactory.getShape = function (typeShape) {
        if (typeShape === "Circle") {
            return new Circle();
        }
        if (typeShape === "Rectangle") {
            return new Rectangle();
        }
        if (typeShape === null) {
            return null;
        }
        return null;
    };
    return ShapeFactory;
}());
// 下面编写测试
var test = ShapeFactory.getShape("Circle");
// 调用draw方法
test.draw();

利用反射改进

class ShapeFactory1 {
    constructor(){

    };
    public static getShape<T extends Shape>(c:{new ():T}):T{    // C类型为类
        return new c();
    }
}
let test = ShapeFactory1.getShape(Circle);
test.draw();

var ShapeFactory1 = /** @class */ (function () {
    function ShapeFactory1() {
    }
    ;
    ShapeFactory1.getShape = function (c) {
        return new c();
    };
    return ShapeFactory1;
}());
var test = ShapeFactory1.getShape(Circle);
test.draw();

工厂方法

即，将工厂拆分

// 工厂方法
class CircleFactory{
    constructor(){

    }
    public static getShape():Shape{
        return new Circle();
    }
}
class RectangleFactory{
    constructor(){

    }
    public static getShape():Shape{
        return new Rectangle();
    }
}
let test = CircleFactory.getShape();
test.draw();

抽象工厂

抽象工厂比较简单不在阐述。
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