JSFiddle - React, Tailwind, and code Playground

CoffeeScript

array = [[1, 5], [4, 7], [3, 8], [2, 3],  
 [12, 4], [6, 6], [4, 1], [3, 2], 
 [8, 14]]

result = Math.max.apply Math, (x[0] for x in array)
 
document.write result