super

super.js

class SuperClass {
  nonarrow() {
    console.log('nonarrow', 'superclass');
  }

  arrow = () => {
    console.log('arrow', 'superclass');
  }
}

class SubClass extends SuperClass {
  nonarrow() {
    super.nonarrow();
    console.log('nonarrow', 'subclass')
  }

  /*
    super.arrow();
          ^

    TypeError: (intermediate value).arrow is not a function
  */
  arrow = () => {
    super.arrow();
    console.log('arrow', 'subclass');
  }
}

const superInstance = new SuperClass();
const subInstance = new SubClass();

console.group('--- superclass calls first ---');
superInstance.nonarrow();
superInstance.arrow();
console.groupEnd();

console.group('--- now the subclass calls. ---');
subInstance.nonarrow();
subInstance.arrow();
console.groupEnd();