I’m trying some tester code
I turn a string into UpperCase
Then split it to make it into an array and then loop through it using ES6 forEach loop
However when I try to concatenate ‘hello’ to the subject of the loop
It returns undefined

```
const string = 'abcd'
console.log(string.toUpperCase().split('').forEach(element => element += 'hello'))

```

And when I add join(‘’) to it it returns this

```
undefined is not an object (evaluating string.toLowerCase().split('').forEach(element => element +=('hello')).join')

```