抽象类工厂模式

<script type="text/javascript">
                            //BMW    Car
    function VehicleFactory(subType, superType) {
        if (typeof VehicleFactory[superType] === ‘function‘) {
            function F() {}
            F.prototype = new VehicleFactory[superType]()
            subType.constructor = subType//prototype已经赋值,下文不能赋值{}，这样会删除以前的原型赋值
            subType.prototype = new F()
        } else {
            throw new Error(‘未创建该抽象类‘)
        }
    }
/* 定义抽象类的结构 */
// 汽车抽象类
    VehicleFactory.Car = function() {
        this.type = ‘car‘
    }
    VehicleFactory.Car.prototype = {
        getPrice() {
            return new Error(‘抽象方法不能调用‘)
        },
        getSpeed() {
            return new Error(‘抽象方法不能调用‘)
        }
    }

// 公交车抽象类
    VehicleFactory.Bus = function() {
        this.type = ‘bus‘
    }
    VehicleFactory.Bus.prototype = {
        getPrice() {
            return new Error(‘抽象方法不能调用‘)
        },
        getPassengerNum() {
            return new Error(‘抽象方法不能调用‘)
        }
    }

// 货车抽象类
    VehicleFactory.Truck = function() {
        this.type = ‘truck‘
    }
    VehicleFactory.Truck.prototype = {
        getPrice() {
            return new Error(‘抽象方法不能调用‘)
        },
        getTrainload() {
            return new Error(‘抽象方法不能调用‘)
        }
    }
//实现具体的类则如下：

// 汽车：宝马具体类
    function BMW(price, speed) {
        this.price = price
        this.speed = speed
    }
    VehicleFactory(BMW, ‘Car‘)
    BMW.prototype.getPrice = function() {
        return this.price
    }
    BMW.prototype.getSpeed = function() {
        return this.speed
    }
    //当需要生产实例时，则：
    
    
    const bmw530 = new BMW(500000, 250)
    console.log( bmw530.getPrice() ) // 500000
    console.log( bmw530.getSpeed() ) // 250 
    console.log( bmw530.type );// ‘Car‘
    
</script>