**Tell us what’s happening:**

Describe your issue in detail here.

I am trying to understand how this recursive method really works as I use another way to solve the problem.

This is based on the **Return Largest Numbers in Arrays** challenge.

I hope somebody can explain It to me.

```
**Your code so far**
```

```
// recursive method that u don't really undestand
function largestOfFour(arr, finalArr = []) {
return !arr.length
? finalArr
: largestOfFour(arr.slice(1), finalArr.concat(Math.max(...arr[0])))
}
largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);
```

```
**Your browser information:**
```

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36`

**Challenge:** Return Largest Numbers in Arrays

**Link to the challenge:**