Having trouble resolving typescript custom path mapping during execution

[NicholasEllul]

Our project makes use of typescript path mapping in order to add custom names to paths in our typescript project. With the following tsconfig.json file we are able to use @utilities as an alias to api/graphql/utils when importing from a file.

{
  "compilerOptions": {
    ...
    "baseUrl": "api",
    "paths": {
      "@utilities/*": ["graphql/utils/*"]
    }
  },
  ...
}

While this works great in VSCode or an IDE resolves these paths in the editor, the typescript team has mentioned that typescript will never convert this alias into its actual import path during runtime. For this reason you get the error Error: Cannot find module '@utilities/user_helper' during an attempt to load the module in a node process. This has prompted packages like https://www.npmjs.com/package/tsconfig-paths to address that issue.

When attempting to run nexus dev while using these custom path mappings the same error comes up for the reasons described above:

 nexus reflection failed
       | error  Error: Cannot find module '@utilities/user_helper'

However, unlike running an app with node where I know the entry point and can call configuration code from tsconfig-path module to resolve these path mappings, I am unable to do so with nexus.

This is because when using the -e flag to specify the entry point for the app, it is not actually the first file being evaluated as behind the scenes nexus has started to scan my files (for types, schema etc.). So when it comes across import {...} from '@utilities/...'; in any of the files, it will raise an error.

Is there any way to work around this ? If not it would be great if nexus had support so that path mappings can be used in the project.

Here are some ideas of possible solutions:

• Perform the resolution of path mappings automatically (ideal solution)
• Expose node's -r flag which would let us preload a module
• Allow for the default entrypoint (or entrypoint specified by -e) to be the first file that is run during nexus' search across project files.

[jasonkuhrt]

Hey @NicholasEllul we're interested in this too. We want the ideal solution, Nexus handling this. You can track the feature and contribute more thoughts at graphql-nexus/nexus#855.