Bonfire: Sum All Numbers in a Range

The Challenge:
We’ll pass you an array of two numbers. Return the sum of those two numbers and all numbers between them.

The lowest number will not always come first.

Helpful Links:

My Solution:

function sumAll(arr) {
  var highestNum = Math.max.apply(null, arr);
  var lowestNum = Math.min.apply(Math, arr);
  var numArr = [];
  for (var i = lowestNum; i <= highestNum; i++) {
  var sumNum = numArr.reduce(function(previousValue, currentValue, currentIndex, array) {
    return previousValue + currentValue;
  return sumNum;

sumAll([1, 4]);

To approach this challenge, I broke it down into small pieces.

1. First I knew I had to get the highest number, so I used the helpful hint of Math.max() to find a way to grab the highest number from the given array.

Because the given numbers are inside of an array, just using Math.max(arr) wouldn’t work. I had to use Math.max.apply(null, arr) to get the highest number.

2. Now that I had the highest number, I needed to find the lowest number in an array.  I used Math.min.apply(Math, arr);

3. I then created a for loop to get all the numbers between my lowest number and my highest number, inclusive.