Arrays - Find missing numbers in a Sequence

Question

I\'m trying to find an easy way to loop (iterate) over an array to find all the missing numbers in a sequence, the array will look a bit like the one below.

var nu

Answer 1

let missing = [];
let numArray = [3,5,1,8,9,36];
const sortedNumArray = numArray.sort((a, b) => a - b);
sortedNumArray.reduce((acc, current) => {
  let next = acc + 1;
  if (next !== current) {
    for(next; next < current; next++) {
      missing.push(next);
    }
  }
  return current;
});