Ability to import event types

Great tool, really really helpful 🙌 This is more of an info sharing issue than anything else, so feel free to close once you’ve seen it.

When using web3, I wanted a way to be able to use the same typed event handling function for both new events and for historical events. This means that event handling function can not be defined in-line, and therefore the function parameters need to be explicitly typed. Because these types aren’t actually exported however, this is not easy to do.

To get at them, I’ve ended up with this EventType type:

export type EventType<E extends ContractEvent<any>> = Parameters<
  Extract<Parameters<E>[1], Function>
>[1]

which I use within my code like so:

type TransferEvent = EventType<Erc20Contract['events']['Transfer']>

I’m posting this issue as it may be helpful for other developers too. It may even make sense to make this, or something like it, directly available from the types.d.ts file.

[krzkaczor]

@AuHau I’ve added exactly this in https://github.com/ethereum-ts/TypeChain/pull/219 For now only for web3v1 branch.

I am gonna reopen this issue until it’s merged.

[AuHau]

Thanks for sharing!

I also think it would be beneficial to export each event as a separate interface that people could import and us.