Function ifNotUndefined

ifNotUndefined<TIn, TOut>(
fn: (value: Exclude<TIn, undefined>) => TOut,
): (value: TIn) => TIn | TOut
Calls a function if the input value is not undefined. Return value from function is passed to next function in flow.
```
const flow = Process.flow(
 Process.max(),
 Process.seenLastToUndefined(),
 Process.ifNotUndefined(v => {
   console.log(`v:`, v);
 })
);
flow(100); // Prints 'v:100'
flow(90);  // Nothing happens max value has not changed
flow(110); // Prints 'v:110'
```
Type Parameters
- TIn
- TOut
Parameters
- fn: (value: Exclude<TIn, undefined>) => TOut
Returns (value: TIn) => TIn | TOut