Abstract constructor type in TypeScript

Question

The type signature for a non-abstract class (non-abstract constructor function) in TypeScript is the following:

declare type ConstructorFunction = new (...ar         


        

Answer 1

Having the same problem. I guess, an essence of abstract class constructor signature is an absense of new ( ... ) : X thingy in its declaration. That's why it can be declared explicitly.

However. You can do this, and it will compile.

var UtilityClass: typeof Utilities  = Utilities;

typeof Something is a nice way to reference constructor types, however, it cannot be extended.

And in any case you can do thing like this:

var UtilityClass: ConstructorFunction = <any> Utilities;

Answer 2

Was just struggling with a similar problem myself, and this seems to work for me:

type Constructor<T> = Function & { prototype: T }

Answer 3

The whole point with abstract classes (in OO in general) is that you can not instantiate them, you need a concrete non-abstract implementation.

I assume that you want to have different implementations to that abstract class and want to be able to receive one of those implementations (as a parameter or something of the likes).
If that's the case, then maybe this might solve your problem:

declare type ConstructorFunction<T extends Utilities> = new (...args: any[]) => T;

abstract class Utilities { }

class MyUtilities extends Utilities { }

var UtilityClass: ConstructorFunction<MyUtilities> = MyUtilities; 

Answer 4

This solution:

type Constructor<T> = Function & { prototype: T }

won't allow you to create instances of this type using new keyword.

There's another simple solution:

type Constructor = new (...args: any[]) => AbstractClass