More on arrays in JS

Following up from 2D array video #46, this interesting solution was pointed out to me in the YouTube comments:

``` javascript
make2Darr = function(r, c) {
return new Array(c).fill([]).map(e => new Array(r));
}
```

Would love to investigate `fill()` and `map()` in a future video. What else? There is also #89 which relates to this topic.