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Comparing arrays

Good day everyone,

I am trying to write a block of code that will compare two arrays and return a new array with any items not found in both of the original two arrays. This should work for numbers and words. For some reason I keep returning an empty array and I can't figure out why. Your help is much appreciated. Nick

```function diff(arr1, arr2) {
var newArr = [];

var filteredOne = arr1.filter(firstFilter);
var filteredTwo = arr2.filter(secondFilter);

newArr = filteredOne.concat(filteredTwo);
return newArr;
}

function firstFilter(value,arr2) {
for (var i = 0; i<arr2.lenth; i++) {
return value !== arr2[i];
}
}

function secondFilter(value,arr1){
for (var i = 0; i<arr1.lenth; i++) {
return value !== arr1[i];
}
}

diff([1, 2, 3, 5], [1, 2, 3, 4, 5]);
```

From my understanding you can't use filter the way that you are using it. If you don't mind not using filter you can do it this way

```<!DOCTYPE html>
<html lang="en">
<meta charset="UTF-8">
<title>Document</title>
<body>
<script>

function getUniqueElements(a1, a2){

//var
var newArray = [];

//loop through the first array
for(var i=0; i < a1.length; i++){

//if the element not present in 2nd array
//push it to newArray
if( a2.indexOf(a1[i]) < 0 ){
newArray.push(a1[i]);
}

}

//return newArray
return newArray;

}

function diff(arr1, arr2){

var uniqueArray1 = getUniqueElements(arr1, arr2);
var uniqueArray2 = getUniqueElements(arr2, arr1);
return uniqueArray1.concat(uniqueArray2);

}

var theDifference = diff([1, 2, 3, 5], [1, 2, 3, 4, 5]);
console.log(theDifference);

</script>
</body>
</html>
```

Bah I was trying to find a way to do it with filter, this is better

Thank you for your help. It is much appreciated. Nick.