diffTwoArrays

******* Optimized 2nd attempt *******
function diffArray(arr1, arr2) {
  var newArr = [];
  function general (array1,array2) {
      for (let i=0;i<array2.length;i++){
    // if the ith index of array 2 matches one of the values in array return true.
        var check = array1.some(function(value){
          return array2[i]===value;
        });
        // if it returns false add it to the new array.
        if (check == false){
          newArr.push(array2[i]);
        }   

      }
  }
  general(arr1,arr2);
  general(arr2,arr1);
  return newArr;
}

diffArray([1, 2, 3, 5], [1, 2, 3, 4, 5]);


********* 1st try ************

function diffArray(arr1, arr2) {
  var newArr = [];
  // use .filter() or/and .every()
  //loop  through array 2
  for (let i=0;i<arr2.length;i++){
    // if the ith index of array 2 matches one of the values in array return true.
    var check = arr1.some(function(value){
      return arr2[i]===value;
    });
    // if it returns false add it to the new array.
    if (check == false){
      newArr.push(arr2[i]);
    }

  }

  for (let j=0;j<arr1.length;j++){
    // if the jth index of array 1 matches one of the values in array return true.
    var check = arr2.some(function(value){
      return arr1[j]===value;
    });
    // if it returns false add it to the new array.
    if (check == false){
      newArr.push(arr1[j]);
    }
  }

  console.log(newArr)  
  return newArr;
}

diffArray([1, 2, 3, 5], [1, 2, 3, 4, 5]);

************* Alternative option workings**************

function diffArray(arr1, arr2) {
  var newArr = [];
  // use .filter() or/and .every()
  //loop  through array 2
  for (let i=0;i<arr2.length;i++){
    // if the ith index of array 2 matches one of the values in array return true.
    var check = arr1.some(function(value){
      return arr2[i]===value;
    });
    // if it returns false add it to the new array.
    if (check == false){
      newArr.push(arr2[i]);
    }

  }

  for (let j=0;j<arr1.length;j++){
    // if the jth index of array 1 matches one of the values in array return true.
    var check = arr2.some(function(value){
      return arr1[j]===value;
    });
    // if it returns false add it to the new array.
    if (check == false){
      newArr.push(arr1[j]);
    }
  }