map<T, R> function
Transform the value of a Task with the provided function.
expect(
await fromThunk(() => 'hi').chain(map((str) => str.toUpperCase()))(),
equals('HI'),
);
Implementation
Task<R> Function(Task<T> task) map<T, R>(R Function(T value) f) =>
(t) => Task(() => t().flatMap(f));