Typescript interfaces allow definition of a function-style call signature thus:

interface A {
    (x: number): number;
}

This can be implemented by, e.g. a function:

const a: A = function(x: number): number {
    return 1;
}

Is it possible to implement such an interface using a class?

I've attempted it like this:

class B implements A {
    (x: number): number {
        return 1;
    }
}

But I get this error:

Class 'B' incorrectly implements interface 'A'. Type 'B' provides no match for the signature '(x: number): number'.ts(2420)

Is there any way to implement this sort of interface using a class in Typescript?