JavaScript Interview Question: Largest integer in array?

find-largest-integer-in-array.js

/* 
Return the largest value in an array of non-negative integers 
*/

function largestInt(arr) {
  if (arr.length === 0) {
    return -1;
  }
  
  return arr.reduce(comparator);
}

const comparator = ((largestValue, element) => largestValue > element ? largestValue : element);

console.log(largestInt([1,2,3,4,5,3,2,1]))