apFn ()

apFn<A, B>(f): ((oa) => Opt<B>)
```
<A, B>(f: (_: A) => B) => (oa: Opt<A>): Opt<B>
```
Apply oa to function f. If argument is None then result is None.
```
apFn(x => x > 0)(opt(1)) // Opt(true)
apFn(x => x > 0)(none) // None
```
Type Parameters
- A
- B
Parameters
- f: ((_) => B)
  - - (_): B
    - Parameters
      _: A
      Returns B
Returns ((oa) => Opt<B>)
- - (oa): Opt<B>
  - Parameters
    - oa: Opt<A>
    Returns Opt<B>
Typeparam
A input of function f

Typeparam
B output of function f
- Defined in Opt.ts:2330