class-transformer's plainToClass: 如何使用此函数将普通文字转换为抽象class？

Question

每当我这样调用 plainToClass 时：

someClass: SomeClass = plainToClass(SomeClass, somePlain)

一切都很好。但是一旦我将 SomeClass 更改为抽象并将上面的内容重写为：

someAbstractClass: SomeAbstractClass = plainToClass(SomeAbstractClass, somePlain)

我收到错误：

No overload matches this call.
  Overload 1 of 2, '(cls: ClassType<BaseFeature>, plain: unknown[], options?: ClassTransformOptions): BaseFeature[]', gave the following error.
    Argument of type 'typeof BaseFeature' is not assignable to parameter of type 'ClassType<BaseFeature>'.
      Cannot assign an abstract constructor type to a non-abstract constructor type.
  Overload 2 of 2, '(cls: ClassType<SomeAbstractClass>, plain: object, options?: ClassTransformOptions): SomeAbstractClass', gave the following error.
    Argument of type 'typeof SomeAbstractClass' is not assignable to parameter of type 'ClassType<SomeAbstractClass>'

难道不能使用 plainToClass 将 plain 转换为 abstractClass 实例吗？为什么不呢？

Answer 1

问题是正常的 class 和抽象的 class 在 TS 中有不同的签名：

export interface AbstractType<T> extends Function {
  prototype: T;
}

export type Type<T> = new (...args: any[]) => T;

由于这个差异，TS 显示错误。

通常不应该有抽象 classes 的实例，只有 classes 的实例实现了它们。不过，您可以使用 any 破解它并获得所需的行为：

const someAbstractClass: SomeAbstractClass = plainToClass(
  SomeAbstractClass as any, // cast to fix the error.
  somePlain,
);

class-transformer's plainToClass: 如何使用此函数将普通文字转换为抽象class？

class-transformer's plainToClass: How to use this function to convert the plain literal to an abstract class?

abstract-class

typescript

class-transformer