Function normalize

normalize<E>(element?: E | E[] | null): E[]
Normalizes a single element or an array of elements into an array. If the input is falsy, returns an empty array.
Type Parameters
- E
Parameters
- Optionalelement: E | E[] | null
  The element or array to normalize
Returns E[]
an array containing the element(s), or an empty array if the input is falsy
Author
David Hsing
Example
```
normalize('foobar');              // ['foobar']
normalize(['foo', 'bar']);        // ['foo', 'bar']
normalize(undefined);             // []
normalize(null);                  // []
```