Function reverseHex

reverseHex(hex?): string | undefined
Returns the reversed hex color from the given color
Parameters
- Optionalhex: string
  the hex color to inspect
Returns string | undefined
the reversed hex color from the given color
Example
```
reverseHex('#000');    // 'rgb(255, 255, 255)'
reverseHex('#fff');    // 'rgb(0, 0, 0)'
```