sum-of-numbers.js

function getSum(a, b) {
  
  // Determine which number is smaller and bigger
  let smallest = a;
  let biggest = b;
  if (b < a) {
    smallest = b;
    biggest = a;
  }
  
  // Sum all the numbers between them (inclusive)
  let sum = 0;
  for (let i = smallest; i <= biggest; i++) {
    sum = sum + i;
  }
  return sum;
}