Demo of generators and iterator

reverseArrayWithIterator.js

let a = [1, 2, 3, 4];

for (let item of a) {
    console.log(item);
}

function* reverse () {
    for (let i = a.length - 1; i >= 0; i--) {
        yield a[i];
    }
}

a[Symbol.iterator] = reverse;

for (let item of a) {
    console.log(item);
}

console.log([...a]);
console.log(a);