PromiEvents and how to implement them #3
Description
According to the Web3JS docs, some functions return something they call a "PromiEvent". Going by their words verbatim:
This “promiEvent” is a promise combined with an event emitter to allow acting on different stages of action on the blockchain, like a transaction. PromiEvents work like a normal promises with added on, once and off functions. This way developers can watch for additional events like on “receipt” or “transactionHash”.
As far as I've noticed, at least the following functions either use, return or depend on this type to work:
- Contract::once()
- Contract::events()
- Contract::allEvents()
- Contract::getPastEvents()
- Eth::sendTransaction()
- Eth::sendSignedTransaction()
- Method::send()
So we have a "promise" part and an "event" part. I'm not sure about this but once we have both parts I'd imagine we could unite their usage in a custom class. The "promise" part is technically fulfilled by std::future, but I don't know what would fulfill the "event"/"listen to events coming from the blockchain" part (if there is anything that would even be able to do that, considering how "stiff" C++ is compared to Javascript in that sense).