Find the first non-consecutive number.js

// DESCRIPTION:
// 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 then return null2.

// The array will always have at least 2 elements1 and all elements will be numbers. The numbers will also all be unique and in ascending order. The numbers could be positive or negative and the first non-consecutive could be either too!

//My Solution

function firstNonConsecutive (arr) {
    let final = 'whatever' 
    for(let i=1; i<arr.length; i++){
      
      if(arr[i] - arr[i-1] !== 1 ){final= arr[i]; break}
      
    }
    if(final !== 'whatever'){return final}
    else{return null}
  }
  firstNonConsecutive([-3,-2,0,1,2])