Error using custom loaders after migrating my project to ESM

[eirikur-nc]

Issue workflow progress

Progress of the issue based on the
Contributor Workflow

• 1. The issue provides a reproduction available on Github, Stackblitz or CodeSandbox

  Make sure to fork this template and run yarn generate in the terminal.

  Please make sure the GraphQL Tools package versions under package.json matches yours.

• 2. A failing test has been provided
• 3. A local solution has been provided
• 4. A pull request is pending review

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Describe the bug

graphql-codegen fails after having added "type": "module" to all packages in a monorepo

To Reproduce:

https://codesandbox.io/p/devbox/q5w2zq

Expected behavior

Being able to author custom data loaders in ESM format

Environment:

• OS: macOs 15.0.1
• @graphql-tools/load: 8.0.0
• NodeJS: 18.18.0

Additional context

I'm working in a monorepo that uses graphql-codegen to generate type information from our GraphQL schema (which has served us well, thanks!)
Due to issues with having a mixture of CommonJS and ESM packages in the repo, we decided to switch entirely over to ESM.
We added "type": "module" to all our package.json files.
We modified our scripts to run graphql-codegen-esm
We have a config file in yml format that specifies custom loaders for two schemas. Example

schema:
  - '${PWD}/src/graphql/types.graphql'
  - ${PWD}/../graphqlSchema.json:
        loader: '${ROOT_PATH}/configs/codegen/fileLoader.js'
  - http://127.0.0.1:5000/api/graphql:
      loader: '${ROOT_PATH}/configs/codegen/urlLoader.js'

Those failed to load properly. I converted them from CommonJS to ESM format and changed their file extensions to *.mjs but that did not suffice.

I found this SO question which got me on the right track
https://stackoverflow.com/questions/75253732/codegen-config-cant-load-custom-schema-loader

In packages/load/src/utils/custom-loader.ts there's a function named getCustomLoaderByPath which uses createRequire which cannot be used to load ES modules. I've managed to work around this issue by patching the package to use a dynamic import instead. The purpose of this issue is to get that change applied upstream to the benefit of others. I will follow up with a PR.

[ardatan]

Thanks for creating the issue.
Could you please create a reproduction on CodeSandbox so we can also debug and help you better with it?

[eirikur-nc]

Thanks for creating the issue. Could you please create a reproduction on CodeSandbox so we can also debug and help you better with it?

Sure: https://codesandbox.io/p/devbox/q5w2zq
I've updated the description with a link

[eirikur-nc]

A PR with a fix is ready for review #6660