It would be helpful to allow a rejection value to be defined to a Promise.

Perhaps this could be defined as Promise<T, U> where U is the rejection value. Any rejection stuff (e.g. reject, Promise.timeout, Promise.now) could use this value to make Promises more type safe.

any: <T>(promises: Array<Promise<T>>) => Promise<T>; 

See https://eryn.io/roblox-lua-promise/api/Promise#any. Ended up with an unexpected bug due to this, thinking it was returning an array.