class Range {
  #start; #end;
  constructor(start, end) { this.#start = start; this.#end = end; }
  [Symbol.iterator]() {
    let current = this.#start;
    const end = this.#end;
    return {
      next() {
        return current < end
          ? { value: current++, done: false }
          : { value: undefined, done: true };
      },
      [Symbol.iterator]() { return this; }
    };
  }
}

const range = new Range(1, 5);
const arr1 = [...range];
const arr2 = [...range];
const sum = arr1.reduce((a, b) => a + b, 0);
console.log(arr1.join(','), arr2.join(','), sum);