js filters out different elements in two sets of arrays

var arr1 = [0, 1, 2, 3, 4, 5];
var arr2 = [0, 2, 3, 4, 5, 6];
function getDifference(arr1, arr2) {
return arr1.concat(arr2).filter(function (item, i, arr) {
return arr.indexOf(item) === arr.lastIndexOf(item)
})
}
console.log(getDifference(arr1, arr2))