find-max-and-min-integers.js

// validate input array elements
function isIntegerArray (input) {
  // if an array
  if (Array.isArray(input)) {
    // if empty array
    if (input.length < 1) return false

    // iterate through each element and return false if one of them happens to be not an integer
    for (let i = 0; i < input.length; i++) {
      if (Number.isInteger(input[i])) continue
      else return false
    }
    return true
  // if not an array
  } else return false
}

function findMaxAndMin (input) {
  // assign first array element to both as initial values
  let max = input[0]
  let min = input[0]

  if (isIntegerArray(input)) {
    // iterate through array starting from second element
    for (let i = 1; i < input.length; i++) {
      // if current element greater than current max, assign it to max
      if (input[i] > max) max = input[i]
      
      // if current element lesser than current min, assign it to min
      if (input[i] < min) min = input[i]
    }

    return { max, min }
  } else return 'Please input an array of integers.'
}

console.log(findMaxAndMin([1, 68, 3, -488, 5, 168, 9, 1, 1]))