Errors when accessing context in resolver-handler.

[heades]

Here is a simple example that illustrates my problem. I have setup graphql-http as follows:

const schema = makeExecutableSchema({
        typeDefs: [typeDefs],
        resolvers: resolvers
    });

app.post('/api', checkJwt, createHandler({ schema , context: (req) => resolverContext(appEnv, req.raw.auth!.payload)}));

where

export interface Context {
    env: Environment,
    auth_payload: JWTPayload
}

export const resolverContext = (env: Environment, payload: JWTPayload): OperationContext => {
    return {env: env, auth_payload: payload};
}

Lastly, my resolver is defined as:

const resolvers = {
    Query: {  
        server: (context: Context): Server => {  
            logDebug(context.env, 'Hit resolver');
            return { say: {hello: "Hello, world!" } };
        }     
    }
}

Now whenever I query my resolver server using

{
  "query": "{ server { say { hello } } }"
}

I get the following:

{
  "errors": [
    {
      "message": "Cannot read properties of undefined (reading 'env')",
      "locations": [
        {
          "line": 1,
          "column": 3
        }
      ],
      "path": [
        "server"
      ]
    }
  ],
  "data": {
    "server": null
  }
}

I don't really understand this error, because env is definitely not undefined. Unless it somehow thinks it's supposed to be part of the schema, but I'm just accessing a passed in parameter. If I remove the logDebug line which removes accessing context.env the query works as expected.

Any help would be appreciated!

[enisdenjo]

The context is not the first argument of graphql-js resolvers, it's the 3rd argument.

const resolvers = {
    Query: {  
-       server: (context: Context): Server => {  
+       server: (_parent, _args, context: Context): Server => {  
            logDebug(context.env, 'Hit resolver');
            return { say: {hello: "Hello, world!" } };
        }     
    }
}

[heades]

Thanks! This helps a lot!