Unable to test custom scalars

[devatina11yb]

Describe the bug

I am currently in the process of developing a few custom scalars for my project, I can manually test the API with GraphiQL but I get a weird bug while testing with vitest.

Here is the verbatim of the error message:

TypeError: Cannot read properties of undefined (reading 'resolve')
 ❯ isResolveOptions node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs:1857:28
 ❯ addObject node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs:1707:22
 ❯ mergeResolvers node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs:1683:21
 ❯ createResolvers node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs:1561:43
 ❯ Object.factory node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs:1949:40
 ❯ node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs:1250:57
 ❯ applicationFactory node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs:1250:40
 ❯ Module.createApplication node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs:1316:12
 ❯ src/index.ts:9:31
      7| const yoga = createYoga({
      8|   graphqlEndpoint: "/",
      9|   plugins: [useGraphQLModules(createApplication({ modules: [scalarsModule] }))],
       |                               ^
     10| });
     11|

To Reproduce

I have published a simplified version of my project in a public repository on GitHub so you can run it on StackBlitz using this URL: https://stackblitz.com/github/devatina11yb/graphql-modules.

To confirm that the API is actually working:

1. Run pnpm run dev.
2. Run the query now in GraphiQL:

query {
  now
}

3. You will get a result looking like this:

{
  "data": {
    "now": 1684752065821
  }
}

To reproduce the bug:

1. Run pnpm run test.
2. You can see the error message in the terminal.

Additional context

It may be worth noting that I actually did find the culprit but I am still struggling to figure out what is going on. The function isScalarResolver is returning false while testing:

// node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs (line 1859)

function isScalarResolver(obj) {
    return obj instanceof GraphQLScalarType;
}

So I added some logging to the function:

// node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs (line 1859)

function isScalarResolver(obj) {
    console.log('obj:', obj, '\nisScalarResolver(obj):', obj instanceof GraphQLScalarType, '\n');
    return obj instanceof GraphQLScalarType;
}

You can also alter the function in StackBlitz by following these steps:

1. Run open /home/projects/qgnikzovb.github/node_modules/.pnpm/graphql-modules@2.1.2_graphql@16.6.0/node_modules/graphql-modules/index.mjs.
2. Go to line 1859.
3. Add console.log('obj:', obj, '\nisScalarResolver(obj):', obj instanceof GraphQLScalarType, '\n'); to the function.

Here is what is displayed in the terminal:

• For pnpm run dev:

obj: { now: [Function: now] }
isScalarResolver(obj): false

obj: GraphQLScalarType {
  name: 'DateTime',
  description: 'DateTime scalar type',
  specifiedByURL: undefined,
  serialize: [Function: serialize],
  parseValue: [Function: parseValue],
  parseLiteral: [Function: parseLiteral],
  extensions: [Object: null prototype] {},
  astNode: undefined,
  extensionASTNodes: []
}
isScalarResolver(obj): true

obj: {
  now: [Function: now] { [Symbol(metadata)]: { moduleId: 'scalars' } }
}
isScalarResolver(obj): false

obj: GraphQLScalarType {
  name: 'DateTime',
  description: 'DateTime scalar type',
  specifiedByURL: undefined,
  serialize: [Function: serialize] { [Symbol(metadata)]: { moduleId: 'scalars' } },
  parseValue: [Function: parseValue] { [Symbol(metadata)]: { moduleId: 'scalars' } },
  parseLiteral: [Function: parseLiteral] {
    [Symbol(metadata)]: { moduleId: 'scalars' }
  },
  extensions: [Object: null prototype] {},
  astNode: undefined,
  extensionASTNodes: []
}
isScalarResolver(obj): true

• For pnpm run test:

obj: { now: [Function: now] }
isScalarResolver(obj): false

obj: GraphQLScalarType {
  name: 'DateTime',
  description: 'DateTime scalar type',
  specifiedByURL: undefined,
  serialize: [Function: serialize],
  parseValue: [Function: parseValue],
  parseLiteral: [Function: parseLiteral],
  extensions: [Object: null prototype] {},
  astNode: undefined,
  extensionASTNodes: []
}
isScalarResolver(obj): false

Environment

• OS: Windows 11
• graphql-modules: 2.1.2
• NodeJS: 20.2.0

[devatina11yb]

This is actually related to the dual package hazard loading CJS and ESM packages from graphql-js at the same time so this is not directly related to graphql-modules. I am closing this issue here.

[DuckThom]

Hi @devatina11yb I was wondering if you found a solution for this as I'm also running into the same error and can't find much information about the issue.

[DuckThom]

I'm not completely sure why, but adding an alias for graphql to my vitest config (and removing the vitest cache node_modules/.vitest) appears to resolve the error.

/// <reference types="vitest" />

import { defineConfig } from 'vitest/config'

// https://vitejs.dev/config/
export default defineConfig({
    resolve: {
        alias: {
            graphql: 'graphql/index.js',
        },
    },
})