Two Pointers Patterns

function twoSumSorted(arr, target) {
  let left = 0;
  let right = arr.length - 1;

  while (left < right) {
    if (arr[left] + arr[right] === target) {
      return [left, right];
    }

    if (arr[left] + arr[right] < target) {
      left++;
    } else {
      right--;
    }
  }

  return [];  
}

;