Find Highest Number in an Array of Numbers

array-find-highest-number.js

const numbersList = [3, 6, 2, 99, 32, 5, 89, 32];
Array.prototype.findHighestNumber = function(currentIndex = 1, lastHighestNumber = this[0]) {
  const currentNumber = this[currentIndex];
  lastHighestNumber = lastHighestNumber > currentNumber ? lastHighestNumber : currentNumber;
  if (currentIndex === this.length - 1) {
    return lastHighestNumber;
  }
  const nextIndex = currentIndex + 1;
  return this.findHighestNumber(nextIndex, lastHighestNumber);
}

console.log(`Highest number in "${numbersList}" is ${numbersList.findHighestNumber()}`);