Accessing and executing function in child class from base class

Question

Is it possible to access child class members and execute child function from base class?

For example:

class ChildClass extends BaseClass {

    protected childMember = 'someName';

    constructor() {
        super();
        super.runBaseFn();
    }

    runChildFn() {
        console.info('child fn');
    }
}

class BaseClass {

    runBaseFn() {
       if (child.childMember === 'someName') {
           child.runChildFn();
       }
    }
}

Is this possible to accomplish the code in runBaseFn ? Or any similar solution?

Answer 1

You'll need to declare that in the parent class:

class BaseClass {
    protected childMember: string;

    runBaseFn() {
       if (this.childMember === 'someName') {
           this.runChildFn();
       }
    }

    protected runChildFn() {}
}

class ChildClass extends BaseClass {
    constructor() {
        super();

        this.childMember = 'someName';
        super.runBaseFn();
    }

    runChildFn() {
        console.info('child fn');
    }
}

( code in playground )

You can make the parent class abstract :

abstract class BaseClass {
    protected childMember: string;

    runBaseFn() {
       if (this.childMember === 'someName') {
           this.runChildFn();
       }
    }

    protected abstract runChildFn();
}