Function emptyAsNull

emptyAsNull<E>(array?: null | E[]): undefined | null | (null | E)[]
Returns a array that replaced the empty element to null from the given array
Type Parameters
- E
Parameters
- Optionalarray: null | E[]
  The arrays to inspect
Returns undefined | null | (null | E)[]
a array that replaced the empty element to null from the given array
Author
David Hsing
Example
```
emptyAsNull(['foo', 'bar']);    // ['foo', 'bar']
emptyAsNull(['foo', '']);    // ['foo', null]
emptyAsNull(['', 'bar']);    // [null, 'bar']
```