In mathematics, interval is the difference between the largest number and the smallest number in an array.
To illustrate:
A = (3, 5, 7, 23, 11, 42, 80)
Interval of A = 80 - 3 = 77
Create a function that takes an array and returns ":)" if the interval of the array is equal to any other element; otherwise return ":(".
faceInterval([1, 2, 5, 8, 3, 9]) ➞ ":)"
// Array interval is equal to one of the other elements.
faceInterval([5, 2, 8, 3, 11]) ➞ ":("
// Array interval is not among the other elements.
faceInterval("bruh") ➞ ":/"
// "bruh" is not an array. It's string.
":/"