Function quoteDouble

quoteDouble(text?: null | string): undefined | null | string
Returns a string that double quotes the given text
Parameters
- Optionaltext: null | string
  the text to inspect
Returns undefined | null | string
a string that double quotes the given text
Author
David Hsing
Example
```
quoteSingle(undefined);    // undefined
quoteSingle('foobar');    // '"foobar"'
```