function * myGenerator () {
    yield 1;
    yield 2;
    yield 3;
    return 4;
}

// If myGenerator was a normal function, myIterator would have the value of 4
// Since it's a generator, myIterator actually contains an iterator object
var myIterator = myGenerator();

// Following logs:
// 1
// 2
// 3
// 4
// to console
var done = false;
while (!done) {
    var current = myIterator.next();
    done = current.done;
    console.log(current);
}