The TypeScript types of the effect functions could be improved:

1. hopeThat

   According to the source code, this function:

   • does not accept an asynchronous callback -- is this intentional?
   • does not use the result of the callback
   • returns a success flag

   Therefore, it can be made non-generic and with a synchronous callback.

   - type HopeThat = <T>(fn: () => Promise<T> | T) => Promise<T | false>;
   + type HopeThat = (fn: () => void) => Promise<boolean>;

2. tryTo

   According to the source code, this function:

   • does not accept an asynchronous callback -- is this intentional?
   • does not use the result of the callback
   • returns a success flag

   Therefore, it can be made non-generic and with a synchronous callback.

   - type TryTo = <T>(fn: () => Promise<T> | T) => Promise<T | false>;
   + type TryTo = (fn: () => void) => Promise<boolean>;

3. retryTo

   According to the source code, this function:

   • expects "maxTries" to be defined
   • accepts optional "pollIntervall"
   • passes iteration index to callback
   • does not use the result of the callback
   • returns a success flag

   Therefore, it can be made non-generic with an extended signature.

   - type RetryTo = <T>(fn: () => Promise<T> | T, retries?: number) => Promise<T>;
   + type RetryTo = (fn: (tries: number) => Promise<void> | void, maxTries: number, pollInterval?: number) => Promise<boolean>;

I would open a PR if intended support for asynchronous callbacks in hopeThat and tryTo is clear.