Your task is to find the first element of an array that is not consecutive. By not consecutive we mean not exactly 1 larger than the previous element of the array. E.g. If we have an array [1,2,3,4,6,7,8] then 1 then 2 then 3 then 4 are all consecutive but 6 is not, so that's the first non-consecutive number. If the whole array is consecutive th…

findTheFirstNonConsecutiveNumber.js

function firstNonConsecutive (arr) {
  const min = Math.min(...arr);
  const max = Math.max(...arr);
  // add missing numbers in the array
  let newArr = Array.from(Array(max-min), (v, i) => {
      return i + min
  });
  // compare the full array with the old missing array
  let filter = newArr.filter(i => {
      return !arr.includes(i)
  });
  
  let nonConsecutivNum = filter[0]+1;

  if (isNaN(nonConsecutivNum)) {
    return null;
  } else {
    return nonConsecutivNum;
  };  
};