Cannot read property 'selections' of null

[dustinfarris]

I am bumping in to this error at this line: https://github.com/mattkrick/cashay/blob/8d9174d478b63883f68b64f82c183b60a3aad0c4/src/normalize/denormalizeStore.js#L34

This started happening after I added a custom type to my schema. When i had "hello" resolving to "world" everything worked fine, but when i tried to create a very basic "user" type, i started seeing this.

I'm not sure what's going on here, could use a point in the right direction.

[mattkrick]

thanks for the bug report! Can you share your schema & query? If not everything, at least the part where it gets tripped up.

[dustinfarris]

Sure!

This is my schema.js which contains everything.

(Note that this is a function because of how I handle importing and passing around graphql)

// graphql/server/schema.js

export default function(graphql) {
  const {
    GraphQLSchema,
    GraphQLObjectType,
    GraphQLString,
    GraphQLNonNull,
    GraphQLID
  } = graphql;

  const User = new GraphQLObjectType({
    name: 'User',
    description: 'Stuff',
    fields: () => ({
      id: {
        type: GraphQLID,
        description: 'the id'
      },
      name: {
        type: GraphQLString,
        description: 'the name'
      }
    })
  });

  const queryType = new GraphQLObjectType({
    name: 'RootQueryType',
    fields: () => ({
      hello: {
        type: GraphQLString,
        resolve() {
          return 'world';
        }
      },
      user: {
        type: User,
        resolve() {
          return { id: '123', name: 'Dustin' };
        }
      }
    })
  });

  return new GraphQLSchema({
    query: queryType
  });
}

[dustinfarris]

Also, the error gets triggered when I run cashay.query({ user })

Running cashay.query({ hello }) works fine.

[dustinfarris]

Updated example with a resolve callback. Still getting the same error.

[dustinfarris]

@mattkrick any idea what might be causing this error? i am not too knowledgable on how ASTs work or what exactly is being done by the offending line, but i want to help!

[mattkrick]

AH! Sorry I replied a few days ago but guess it didn't make it to github. Thanks for the ping! I think the cause is that you're returning a string instead of a document (complete with an id field). Nevermind, those tests are still working properly. Lemme copy over your example schema & see if i can reproduce.

[mattkrick]

okie doke, so the problem is that your query isn't valid. GraphQL is super declarative, so you'd need to write:

user {
  id
  name 
}

Otherwise, it doesn't know what fields to grab for ya.

That said, Cashay should probably throw up a useful warning message. I'll fix that

[dustinfarris]

Thanks for the quick feedback. I'll give it a try later today.

[dustinfarris]

Adding the fields works. Thanks!

FYI, if the id field is omitted, I get this error:

Uncaught TypeError: Cannot read property 'find' of undefined

occurring at this line:

https://github.com/mattkrick/cashay/blob/master/src/normalize/normalizeResponse.js#L52

maybe this needs a friendlier error as well?

[mattkrick]

that sounds good, i'll add that to the PR

[dustinfarris]

Awesome! Thanks for the quick feedback. I'll make the adjustment, and close after I verify.

Sent from my iPhone

On Oct 23, 2016, at 8:55 AM, Matt Krick notifications@github.com wrote:

okie doke, so the problem is that your query isn't valid. GraphQL is super declarative, so you'd need to write:

user { id name } Otherwise, it doesn't know what fields to grab for ya.

That said, Cashay should probably throw up a useful warning message. I'll fix that

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[mattkrick]

Ah, you know what, I don't think I planned for any query from the root query to return a primitive. Usually a query returns a document that includes an ID field. If you don't have an ID, then it can't really cache it efficiently. I'll dig in and see if I can reproduce.

On Fri, Oct 21, 2016, 8:43 AM Dustin Farris notifications@github.com wrote:

Updated example with a resolve callback. Still getting the same error.

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Reply to this email directly, view it on GitHub https://github.com/mattkrick/cashay/issues/131#issuecomment-255412383, or mute the thread https://github.com/notifications/unsubscribe-auth/AFQjv6hwVMrDliRmOJ22jIssM0XrNcA4ks5q2N2ygaJpZM4KdWC0 .