SOURCE

var uniqueInOrder = function (iterable) {
    //your code here - remember iterable can be a string or an array
    const len = iterable.length;
    const result = [];

    for (let i = 0; i < len; i++) {
        if (iterable[i] !== iterable[i + 1]) {
            result.push(iterable[i]);
        }
    }
    console.log(result);
    return result;
};
uniqueInOrder('AABBCcDD');