I’m currently facing a challenge while attempting to incorporate a standard abstract factory pattern in Typescript, only to find that the compiler is not quite on board with my efforts. Below is a simplified version of the code I am working with:
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 OCCURS HERE
}
}
class UserFactory extends ModelFactory<typeof User> {
constructor() {
super(User);
}
}
let user: User;
user = new UserFactory().create();
Upon compiling using tsc 2.1, an error arises at the aforementioned line:
model.ts(8,13): error TS2511: Cannot create an instance of the abstract class 'Model'.
If the line is adjusted as follows by excluding type safety:
return new (this.modelConstructor as any)();
The code compiles without errors. Nonetheless, this workaround is less than ideal. Is there an alternative method to ensure compilation without resorting to a cast? And if this isn’t feasible, could you provide some insight into why?