How to use a class type as a typed variable? (Typescript)

Question

Lets say you have an interface then classes that implement it.

interface A { /*do stuff*/ }

class B implements A { /*do stuff*/ }

class C implements A { /*do stuff*/ }

Then if you have a variable that can store the class type, not a specific instance of an object, what do you put as the type?

let x: Something = B; // or C

I know for objects you can use typeof, but for interfaces you can't. However I am able to specify variables to store implementations of interfaces so I don't see why I shouldn't be able to store classes of an interface.

Titian Cernicova-Dragomir · Accepted Answer · 2020-05-25 12:54:12Z

1

You can use a constructor signature (similar to a function signature, but with a new in front of it):

interface A { /*do stuff*/ }

class B implements A { /*do stuff*/ }

class C implements A { /*do stuff*/ }


let x: new () => A = B;
let x2: new () => A = C;

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answered May 25, 2020 at 12:54

Titian Cernicova-Dragomir

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