const arr = ['h', 'e', 'l', 'l', 'o'];
let arrIterator = arr[Symbol.iterator]();
console.log(arrIterator.next()); // {value: "h", done: false}
console.log(arrIterator.next()); // {value: "e", done: false}
console.log(arrIterator.next()); // {value: "l", done: false}
console.log(arrIterator.next()); // {value: "l", done: false}
console.log(arrIterator.next()); // {value: "o", done: false}
console.log(arrIterator.next()); // {value: undefined, done: true}