LeetCode 136. Single Number JavaScript Solution: One Line

A brief walkthrough of LeetCode problem 136, Single Number, in JavaScript. The intuition is that identical pairs of numbers put in a sequence joined by XOR will eliminate, and these pairs do not have to be adjacent in the sequence for the elimination to take place. If there is one 'Single Number' that is not paired, but is in the sequence joined by XOR, that 'Single Number' will be all that remains.