❗️Что будет на выходе:

class Counter {
  constructor(max) {
    this.max = max;
  }
  
  *[Symbol.iterator]() {
    let current = 0;
    while (current < this.max) {
      yield current++;
    }
  }
}

const counter = new Counter(3);
const result = [...counter, ...counter];
console.log(result);

Ответ: [0, 1, 2, 0, 1, 2]

JavaScript test | #JavaScript