Function nullable

nullable<T>(predicate: TypePredicateFn<T>): TypePredicateFn<T | null>
Create a type predicate function that passes if input is null or passes the given predicate.
Type Parameters
- T
Parameters
- predicate: TypePredicateFn<T>
Returns TypePredicateFn<T | null>
Example
```
const isNullableString = nullable(isString);
isNullableString('hello'); // true
isNullableString(null); // true
isNullableString(undefined); // false
```
- Defined in src/predicate/factory/nullable.ts:15