Let's get an array of digits of a number. Let the following number be given:

`let num = 12345;`

Trying to expand a number in
terms of `spread`

will
result in an error, since
numbers are not iterable:

```
let num = 12345;
let arr = [...num]; // an error
console.log(arr);
```

To solve the problem, we convert the number to a string:

```
let num = 12345;
let arr = [...String(num)];
console.log(arr); // ['1', '2', '3', '4', '5']
```

We, however, have an array of
strings, not numbers. Let's
fix the problem with a trick
using the
`map`

method:

```
let num = 12345;
let arr = [...String(num)].map(Number);
console.log(arr); // [1, 2, 3, 4, 5]
```

Given a number. Find the sum of its digits.