ES6 Classes & Constructors

class Counter {
  #count = 0;
  
  increment() {
    this.#count++;
  }
  
  getCount() {
    return this.#count;
  }
}

Public fields
Private methods
Private fields
This demonstrates private class fields: 1) The # prefix denotes a truly private field, 2) Private fields cannot be accessed or modified outside the class, 3) Attempting to access private fields from outside the class throws an error, 4) This provides proper encapsulation at the language level, 5) This is a relatively new feature in JavaScript (ES2022), 6) Private fields offer better security than the previous convention of using underscore prefixes which were just a naming convention and not actually private.
Static properties