2048

2D array manipulation with merge logic that combines adjacent equal values.

function mergeRow(row) {
  const filtered = row.filter(x => x);
  for (let i = 0; i < filtered.length - 1; i++) {
    if (filtered[i] === filtered[i + 1]) {
      filtered[i] *= 2;
      filtered.splice(i + 1, 1);
    }
  }
  return filtered;
}