strict classes

Javascript is known of no having privates and no members (are plain functions). Recently a new proposal has raised for the standard to have privates using the # symbol.

This package creates a new method of creating class constructors that have methods and everything else is private.

import strict from 'strict-classes';
 
class Animal {
  constructor(name, sound) {
    this.name = name;
    this.#sound = sound;
  }
  getName() {
    return this.name;
  }
  getSound() {
    return this.#sound;
  }
}
 
const animal = new Animal('yogi', 'nyam');
expect(animal.getName()).toBe('yogi')
expect(animal.getSound()).toBe('nyam')
expect(animal.name).toBe('yogi')
// animal.#sound throws
let {getName, getSound} = animal;
// getName() throws
// getSound() throws
 
const StrictAnimal = strict(Animal);
const strictAnimal = new StrictAnimal('yogi', 'nyam');
expect(strictAnimal.getName()).toBe('yogi')
expect(strictAnimal.getSound()).toBe('nyam')
expect(strictAnimal.name).toBeUndefined()
// animal.#sound throws
({getName, getSound} = animal);
expect(getName()).toBe('yogi')
expect(getSound()).toBe('nyam')

Accessing the public this

There are two this, the private this, only visible by the class, and the public this, visible by anyone.

The class itself can ask for the public this by calling getPublicThis.

import strict, { getPublicThis } from 'strict-classes';
 
class Animal {
  getName() {
    return this.name;
  }
  setName(name) {
    this.name = name;
    return getPublicThis(this);
  }
}
 
const animal = new Animal();
expect(animal.setName()).toBe(animal);
expect(animal.setName('yogi').getName()).toBe('yogi');