本文介绍了如何在Typescript中创建抽象工厂模式?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我正在尝试在Typescript中实现标准的抽象工厂模式,但是编译器无法协同工作.这是我的代码的简化版本:
I am trying to implement a standard abstract factory pattern in Typescript, but the compiler is not being cooperative. Here is a simplified version of my code:
abstract class Model { }
class User extends Model { }
abstract class ModelFactory<T extends typeof Model> {
constructor(private modelConstructor: T) {}
public create(): T {
return new (this.modelConstructor)(); // ERROR HERE
}
}
class UserFactory extends ModelFactory<typeof User> {
constructor() {
super(User);
}
}
let user: User;
user = new UserFactory().create();
但是,当我使用tsc 2.1进行编译时,在上面指出的行上出现了以下错误:
However, when I compile using tsc 2.1, I get the following error at the line indicated above:
model.ts(8,13): error TS2511: Cannot create an instance of the abstract class 'Model'.
如果我删除安全类型并将行转换为此:
If I remove type safety and convert the line to this:
return new (this.modelConstructor as any)();
代码编译无误.但是,这是不幸的.有没有什么方法可以在不使用强制转换的情况下使此代码可编译?如果没有,为什么不呢?
The code is compiled without errors. However, this is unfortunate. Is there any way to make this code compilable without using a cast? And if not, why not?
推荐答案
您应改用以下模式:
abstract class ModelFactory<T extends Model> {
constructor(private modelConstructor: new () => T) { }
public create(): T {
return new (this.modelConstructor)(); // OK!
}
}
class UserFactory extends ModelFactory<User> {
constructor() {
super(User);
}
}
这篇关于如何在Typescript中创建抽象工厂模式?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!