Type error when using a baseURL and paths in a next project

[csprance]

I get this error when I go to build or type check with TSC on my NextJS 12 Project.

node_modules/iron-session/next/index.ts:8:48 - error TS2307: Cannot find module '../src/getPropertyDescriptorForReqSession' or its corresponding type declarations.

8 import getPropertyDescriptorForReqSession from "../src/getPropertyDescriptorForReqSession";
                                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

in my tsconfig.json it looks like

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@/*": ["*"]
    },
    "target": "es5",
    "lib": ["dom", "dom.iterable", "esnext"],
    "allowJs": true,
    "skipLibCheck": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "noEmit": true,
    "esModuleInterop": true,
    "module": "esnext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "jsx": "preserve",
    "jsxImportSource": "@emotion/react",
    "incremental": true
  },
  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx"],
  "exclude": ["node_modules"]
}

If I remove these bits

    "baseUrl": ".",
    "paths": {
      "@/*": ["*"]
    },

Works just fine but I'd really love to be able to use alias'.

Is this something that can be changed on a package side or is it just a configuration problem on my side?

[adarnon]

Any chance this can be merged? It's also happening to us

[vvo]

Hey I am confused because I also use baseUrl: "." in my projects so I am wondering what's really wrong here? If someone can reduce the necessary changes too that would be great. The current PR for this (thanks @csprance) includes multiple things I don't get why the library should be doing.

Importing a file with a relative path in the library shouldn't trigger an issue on the consumer side. Please provide some more information/dig more if possible with reference links to issue on TS/Next. Thanks!

[zunkelty]

I had the same problem and could solve it by changing the import path. Before I imported modules from iron-session/next which resulted in the error described by @csprance. Changing the path to iron-session/next/dist fixed it.

[csprance]

I'm not sure why it happens I just know this fixes it. I was using a bunch of different libs and this was the only one that had issues with baseURL.

In the end I just ended up duplicating the lib in my own codebase to deal with the changes.

[vvo]

Hey there, you can see that our official TypeScript example is also using baseUrl as seen here: https://github.com/vvo/iron-session/blob/f9d0351e11c2553ad605f17cf1c139b79eee1db1/examples/next.js-typescript/tsconfig.json#L20 and we then import this way: https://github.com/vvo/iron-session/blob/f9d0351e11c2553ad605f17cf1c139b79eee1db1/examples/next.js-typescript/pages/api/login.ts#L4 which has no problem.

So most probably there's something different in your setup and you'll need to find what's the difference. Thanks!

[csprance]

I don't think the issue is with the baseURL it's with the path section.

[jamiter]

Same issue here. Had to import it from /dist as well as mentioned here: https://github.com/vvo/iron-session/issues/455#issuecomment-1100040845

For context, this is an issue with Jest which isn't able to resolve ESM that well.

[JulianKingman]

It looks like the package has an import that's depending on something in the src folder, which I'm guessing is removed from the deployed package (and replaced with dist).