maxCounters.js

function solution(N, A) {
    var counters = new Array(N);
    var max = 0;
    var toBeAppliedMax = 0;

    for (let K = 0; K < A.length; K++) {
        const op = A[K];
        if (op == N + 1) {
            toBeAppliedMax = max;
        }
        if (op >= 1 && op <= N) {
            const counterInx = op - 1;
            let currVal = counters[counterInx] || 0;
            if (currVal < toBeAppliedMax)
                currVal = toBeAppliedMax;
            currVal++;
            counters[counterInx] = currVal;
            if (max < currVal) max = currVal;
        }
    }
    counters = [...counters].map(p => Math.max((p || 0), toBeAppliedMax));
    return counters;
}