Function isTheme

isTheme(
value: Record<string, unknown> | undefined,
): value is Record<string, unknown> & Theme
Whether a host-supplied theme has the colours NAP-THEME requires.
Parameters
- value: Record<string, unknown> | undefined
  The theme option as the host passed it.
Returns value is Record<string, unknown> & Theme
True when colors.background, colors.text and colors.primary are strings.
Example
```
isTheme({ colors: { background: '#000', text: '#fff', primary: '#7aa2f7' } }); // true
```