Events and logging
We have seen the use of events in previous chapters without going into any detail. In this section, however, we will look at events in more depth. Events are well known to event-driven programmers. Events refer to the notification of state change or an act of action in contracts to external entities such that they can react and take related actions.
Events help us to write asynchronous applications. Instead of continuously polling the Ethereum ledger for the existence of a transaction and then blocking with certain information, the same procedure can be implemented using events. This way, the Ethereum platform will inform the client if an event has been raised. This helps when writing modular code and also conserves resources.
It is to be understood that events do not directly associate themselves with any external entities. As we know that function execution in Ethereum happens much later while a block is getting added to the chain, the function cannot have...