Function toStringOnOff

toStringOnOff(value?: boolean): undefined | string
Returns a string value of 'on'/'off' from the boolean value
Parameters
- Optionalvalue: boolean
  the boolean value to check
Returns undefined | string
the string value of 'on'/'off' from the boolean value
Author
David Hsing
Example
```
toStringOnOff(true);    // 'on'
```