Question

是否可以将以下代码转换为使用Typescript？

public shops: string[] = [
   "AShop",
   "BShop",
   "CShop",
];    

this.shops.forEach((shop, index) => {
    let instance = new window[shop](index);
    this.instances.push(instance);
});

以下方法不适用于Typescript，因为范围内不存在window。我无法编译它。（虽然它适用于香草JS）

有没有办法将循环中的变量名shop视为表达式并基于它创建动态类？

Answer 1

试试这个：

const shops: string[] = ["AShop", "BShop", "CShop"];

class BaseShop {
    public constructor(index: number) {
        console.log(index);
    }
 }

class AShop extends BaseShop { }
class BShop extends BaseShop { }
class CShop extends BaseShop { }

interface ShopContructor {
    new (index: number): BaseShop;
}

interface Window {
    AShop: ShopContructor;
    BShop: ShopContructor;
    CShop: ShopContructor;
    [shop: string]: ShopContructor;
}

window.AShop = AShop;
window.BShop = BShop;
window.CShop = CShop;

const instances: BaseShop[] = [];

shops.forEach((shop: string, index: number) => {
    let instance = new window[shop](index);
    instances.push(instance);
});

console.log(instances);

Answer 2

这是一个奇怪的结构，因为如果在全局范围内有动态类，则在编译时无法对其进行良好的类型检查。我建议在这里使用<any>并将其完成。如果您希望生成的实例具有某些类型保证，则应使用变量类型或强制转换显式指定它们：

this.shops.forEach((shop, index) => {
    let instance = new (<any>window)[shop](index);
    this.instances.push(instance);
});

使用Typescript通过变量创建类实例

2 个答案: