Length of a Nested Array

The .length property on an array will return the number of elements in the array. For example, the array below contains 2 elements:

[1, [2, 3]]
// 2 elements, number 1 and array [2, 3]

Suppose we instead wanted to know the total number of non-nested items in the nested array. In the above case, [1, [2, 3]] contains 3 non-nested items, 1, 2 and 3.

Write a function that returns the total number of non-nested items in a nested array.

Examples

getLength([1, [2, 3]]) ➞ 3

getLength([1, [2, [3, 4]]]) ➞ 4

getLength([1, [2, [3, [4, [5, 6]]]]]) ➞ 6

getLength([1, [2], 1, [2], 1]) ➞ 5

Notes

An empty array should return 0.