How to create Iterable object which chains JavaScript Iterator objects

chained.js

function chained(...iterators) {
    return {
        [Symbol.iterator]() {
            return {
                next() {
                    if (iterators.length === 0) {
                        return { done: true };
                    }

                    const result = iterators[0].next();
                    if (!result.done) {
                        return result;
                    }

                    iterators.shift();
                    return this.next();
                }
            }
        }
    }
}

const it1 = [1, 2, 3].values();
const it2 = [4, 5, 6].values();
const it3 = [7, 8, 9].values();

for (const i of chained(it1, it2, it3)) {
    console.log(i);
}