Type annotations for DataLoader

I just started experimenting with aiodataloader and it’s been great so far. Having type annotations (at least for the public DataLoader class) would make it even easier for folks who are leveraging Python’s typing system.

From a preliminary look it seems like adding the basics for the DataLoader would be pretty straightforward. We would need to accept a type for the KeyType and ValueType. I think it would look something like

from aiodataloader import DataLoader

class UserLoader(DataLoader[int, User]):
    async def batch_load_fn(self, keys: Sequence[int]) -> Sequence[User]:
        return await my_batch_get_users(keys)

user_loader = UserLoader()

I may have some time to try doing this myself. If I do would you be interested in accepting the patch?

[markedwards]

Following up here, @aawilson has a PR that is nearing completion, and will result in a fully-typed release of aiodataloader (I expect this to be 0.3.0).

@erikwrede, ideally graphene should switch back to using this library directly, since it is in fact maintained and we are moving forward now with improvements. What do you think?

[markedwards]

@allancaffee, I’ve already done work to implement typing on top of aiodataloader. How about I get a PR done in the next week or two, and you can take a look?