React-apollo: Is it possible to use the default 'dataIdFromObject' when specifying 'customResolvers'

[MichaelDeBoey]

After reading part 5 of the _Full-stack GraphQL + React Tutorial_, I was just wondering if it's possible to use the default dataIdFromObject when specifying the customResolvers?

It looks a bit cumbersome to _reïmplement_ the default dataIdFromObject if you're happy with that one isn't it?
But I couldn't find a way to access it so I could use it in the customResolvers definition. 😕

[helfer]

@MichaelDeBoey yes you can! Maybe it's not well documented, but you can access the function that the client instance uses as client.dataIdFromObject.

[MichaelDeBoey]

@helfer So you could use the following then?

import {ApolloClient, toIdValue} from 'react-apollo';

const client = new ApolloClient({
  customResolvers: {
    Query: {
      channel: (_, args) => {
        return toIdValue(ApolloClient.dataIdFromObject({ __typename: 'Channel', id: args['id'] }))
      },
    },
  },
});

[helfer]

Yes, but you'll have to replace ApolloClient.dataIdFromObject with client.dataIdFromObject.

[MichaelDeBoey]

@helfer But I'm still initializing the client here (i.e new ApolloClient) so...

[helfer]

I know, but just give it a try, it should work. The wonders of JavaScript! 😉

[MichaelDeBoey]

OK now I feel really dumb 😛 😓 😞
Why's this even possible? 😮

[helfer]

It's only possible because the custom resolve function only runs after the client has been initialized. If it was run during the initialization then you're definitely right that it wouldn't work. GraphQL-js uses thunks for defining fields for the same reason (circular references).

[MichaelDeBoey]

Thanks for the explanation @helfer 😉