### capitalize

Capitalizes the first letter of a string.

Use array destructuring and `String.toUpperCase()` to capitalize first letter, `...rest` to get array of characters after first letter and then `Array.join('')` to make it a string again.
Omit the `lowerRest` parameter to keep the rest of the string intact, or set it to `true` to convert to lowercase.

```js
const capitalize = ([first, ...rest], lowerRest = false) =>
  first.toUpperCase() + (lowerRest ? rest.join('').toLowerCase() : rest.join(''));
```

```js
capitalize('fooBar'); // 'FooBar'
capitalize('fooBar', true); // 'Foobar'
```