andThenAsyncForOption

Returns None if the input is None, otherwise calls transformer with the value and returns the result.

XXX: Some languages call this operation flatmap. But we don't provide flatMap() as alias of this function to sort with other APIs.

function andThenAsyncForOption<T, U>(input: Option<T>, transformer: OptionAsyncTryTransformFn<T, U>): Promise<Option<U>>;

andThenAsyncForOption<T, U>(input: Option<T>, transformer: OptionAsyncTryTransformFn<T, U>): Promise<Option<U>>

input: Option<T>

transformer: OptionAsyncTryTransformFn<T, U>

Promise<Option<U>>