JAVASCRIPT

largest element in nested array

function largestOfFour(arr) {
  const results = [];
  for (let i = 0; i < arr.length; i++) {
    let largestNumber = arr[i][0];
    for (let j = 1; j < arr[i].length; j++) {
      if (arr[i][j] > largestNumber) {
        largestNumber = arr[i][j];
      }
    }
    results[i] = largestNumber;
  }

  return results;
}

largest element in nested array

function largestOfFour(arr) {
  return arr.map(function(group) {
    return group.reduce(function(prev, current) {
      return current > prev ? current : prev;
    });
  });
}

largest element in nested array

function largestOfFour(arr, finalArr = []) {
  return !arr.length
    ? finalArr
    : largestOfFour(arr.slice(1), finalArr.concat(Math.max(...arr[0])))
}