I'm a little baffled. For some reason this won't work:

```
[1, 2, 3].forEach(function(num) {
  console.log(num)
})

```

I get this error:

```
TypeError: Cannot call method 'forEach' of undefined

```

However, this will:

```
var nums = [1, 2, 3]

nums.forEach(function(num) {
  console.log(num)
})

```

Anyone have any idea what's going on here?