05. Unity

class Rat {
  constructor(name) {
    this.name = name;
    this.rats = [];
  }

  getRats() {
    return this.rats;
  }

  unite(otherRat) {
    return otherRat.constructor.name === this.constructor.name && this.rats.push(otherRat);
  }

  toString() {
    return this.name;
  }
}