Using static property in inherited class method

Question

This piece of code transpiles with Babel and TypeScript and works as expected.

class ParentClass {
    static staticProp = true; 

    method() {
        console.log(this.constructor.staticProp);
    }
}

class ChildClass extends ParentClass {
    static staticProp = false;
}

(new ChildClass).method(); 

The requirement here is to refer to static property of current class (through this.constructor) instead of mentioning the class explicitly, so the method can be inherited and use the relevant static property in child classes.

It is ok for Babel, and TypeScript compiles it as well, but it throws

error TS2339: Property 'staticProp' does not exist on type 'Function'.

on compilation.

How can this case be treated to please TypeScript compiler?

Answer 1

TypeScript only supports ClassName.staticPropertyName syntax at the moment. There is, however, an open issue asking for simplifying it.

You can also wrap your staticProp in a getter. It's cumbersome but at least it does not feel like a language hack:

class ParentClass {
    static staticProp = true; 

    method() {
        console.log(this.staticProp);
    }

    get staticProp(): boolean { return ParentClass.staticProp; }
}

class ChildClass extends ParentClass {
    static staticProp = false; 

    get staticProp(): boolean { return ChildClass.staticProp; }
}

(new ChildClass).method(); 

Answer 2

I was able to make TypeScript keep silent with

class ParentClass {
    static staticProp = true; 

    method() {
        console.log((<typeof ParentClass>this.constructor).staticProp);
    }
}