Java style JS comparator

Comparator.js

let log = console.log.bind (console);

class Comparator
{
  static #strCompararor = (f, s) => f.localeCompare (s);
  static #numComparator = (f, s) =>
    (f < s) ? -1 : (f > s) ? 1 : 0;
  
  static strComparator () { return this.#strCompararor; }
  static numComparator () { return this.#numComparator; }
  
  static #IC = class IC
  {
    #extractorAndConparators;
    
    constructor (keyExtractor, keyComparator)
    {
      this.#extractorAndComparators = [[keyExtractor, keyComparator]];
    }
    
    thenComparing (keyExtractor, keyComparator = Comparator.strComparator ())
    {
      this.#extractorAndComparators.push ([keyExtractor, keyComparator]);
      return this;
    }
    
    compare (ob1, ob2)
    {
      for (let [keyExtractor, keyComparator] of this.#extractorAndComparators)
      {
        let key1 = keyExtractor (ob1);
        let key2 = keyExtractor (ob2);
        let res = keyComparator (key1, key2);
        if (res !== 0)
          return res;
      }
      return 0;
    }
  }
  
  static comparing (keyExtractor, keyComparator = Comparator.strComparator ())
  {
    return new Comparator.#IC (keyExtractor, keyComparator);
  }

  constructor ()
  {
    throw new Error ("Shouldn't be called");
  }
  
  compare ()
  {
    throw new Error ("Shouldn't be called");
  }
}

let f = { a : { a1: 'ACCC', b : {b1: 10, name: 'Bbc'} } };
let s = { a : { a1: 'CCC', b : {b1: 10, name: 'Bbc'} } };

log (Comparator.comparing (o => o.a.a1)
  .thenComparing (o => o.a.b.b1, Comparator.numComparator ())
  .thenComparing (o => o.a.b.name)
  .compare (f, s));