diff arrays Javascript

gistfile1.js

const arr1 = [1, 2, 3, 4, 5];
const arr2 = [0, 2, 4, 6, 10, 11];
const DIFF = [1, 3, 5, 0, 6, 10, 11];


function diffWithFor(arr1, arr2) {
  const holderArr = [];
  for(let i = 0; i < arr1.length; i++) {
    if (arr2.indexOf(arr1[i]) === -1) {
      holderArr.push(arr1[i]);
    }
  }
  for(let j = 0; j < arr2.length; j++) {
    if(arr1.indexOf(arr2[j]) === -1) {
      holderArr.push(arr2[j]);
    }
  }
  return holderArr;
  
}

const arrDiff1 = diffWithFor(arr1, arr2);
console.assert(JSON.stringify(arrDiff1) === JSON.stringify(DIFF), '#diffWithFor Show this if it is not equal to');

function diffWithFilter(arr1, arr2) {
  const tempArr1 = arr1.filter(item => arr2.indexOf(item) === -1);
  const tempArr2 = arr2.filter(item => arr1.indexOf(item) === -1);
  const holderArr = tempArr1.concat(tempArr2);
  return holderArr;
}

const arrDiff2 = diffWithFilter(arr1, arr2);
console.assert(JSON.stringify(arrDiff2) === JSON.stringify(DIFF), '#diffWithFilter Show this if it is not equal to');
// console.log(arrDiff2)

function diffWithFilterAlternative(arr1, arr2) {
  return arr1.filter(item => arr2.indexOf(item) === -1)
    .concat(arr2.filter(item => arr1.indexOf(item) === -1));
}

const arrDiff3 = diffWithFilterAlternative(arr1, arr2);
console.assert(JSON.stringify(arrDiff3) === JSON.stringify(DIFF), '#diffWithFilterAlternative Show this if it is not equal to');
// console.log(arrDiff3)