class Foo {
  #start = 0;
  #end = 0;

  constructor(end) {
    this.#end = end;
  }

  async *[Symbol.asyncIterator]() {
    while (this.#start <= this.#end) {
      yield new Promise((resolve) => resolve(this.#start++));
    }
  }
}

const bar = new Foo(10);

for await (const i of bar) {
  console.log(i);
}