Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: No "exports" main defined when use cjs/mjs config

[azu]

@file-cache has used packemon for packaging.

• https://github.com/azu/file-cache/blob/26d5a23128bfcb5680c007fedc5607c737a87780/.moon/project.yml#L19-L38

And, packemon config is following.

  "packemon": [
    {
      "inputs": {
        "index": "./src/index.ts"
      },
      "platform": "node",
      "format": "cjs"
    },
    {
      "inputs": {
        "node": "./src/index.ts"
      },
      "platform": "node",
      "format": "mjs",
      "support": "experimental"
    }
  ],

https://github.com/azu/file-cache/blob/26d5a23128bfcb5680c007fedc5607c737a87780/packages/core/package.json#L13-L29

I aim to publish dual package CJS/MJS.
I've published this package, but this package can not be required from CJS.

It means that require("@file-cache/core") throw an error.

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: No "exports" main defined

Expected

No Error on require("@file-cache/core")

Actual

Can not require("@file-cache/core").
However, import * from "@file-cache/core" is work.

node:internal/modules/cjs/loader:488
      throw e;
      ^

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: No "exports" main defined in /Users/azu/ghq/github.com/azu/packemon-require-filed-missing/node_modules/@file-cache/core/package.json
    at new NodeError (node:internal/errors:372:5)
    at throwExportsNotFound (node:internal/modules/esm/resolve:472:9)
    at packageExportsResolve (node:internal/modules/esm/resolve:693:7)
    at resolveExports (node:internal/modules/cjs/loader:482:36)
    at Function.Module._findPath (node:internal/modules/cjs/loader:522:31)
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:919:27)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (/Users/azu/ghq/github.com/azu/packemon-require-filed-missing/index.js:1:1) {
  code: 'ERR_PACKAGE_PATH_NOT_EXPORTED'
}

Details

Published @file-cache/core/package.json is following:

  "types": "./dts/index.d.ts",
  "main": "./cjs/index.cjs",
  "exports": {
    "./package.json": "./package.json",
    "./*": {
      "types": "./dts/*.d.ts",
      "node": {
        "import": "./mjs/*.mjs"
      }
    },
    ".": {
      "types": "./dts/index.d.ts",
      "node": {
        "import": "./mjs/index.mjs"
      }
    }
  }

I've noticed that that Conditional exports does not define require field like "require": "./cjs/index.cjs".

I mofify node_modules/@file-cache/core/package.json directory and require("@file-cache/core") is work.

  "types": "./dts/index.d.ts",
  "main": "./cjs/index.cjs",
  "exports": {
    "./package.json": "./package.json",
    "./*": {
      "types": "./dts/*.d.ts",
      "node": {
        "import": "./mjs/*.mjs"
      }
    },
    ".": {
      "types": "./dts/index.d.ts",
      "node": {
        "import": "./mjs/index.mjs"
+       "require": "./cjs/index.cjs"
      }
    }
  }

packemon format the exports field automatically. So I can not add require or default property to node.

Reproduce repository

• https://github.com/azu/packemon-require-filed-missing

Env

• packemon@2.3.1
• node@16.15.0
• npm@8.13.2

Note

• How Jotai Specifies Package Entry Points · Daishi Kato's blog

[azu]

I've created minimal reproduce
https://github.com/azu/packemon-cjs-issue

[milesj]

@azu Thanks, this should fix it #136

On a side note, I suggest not using cjs/mjs in parallel as you run the risk of the dual package hazard. https://nodejs.org/api/packages.html#dual-commonjses-module-packages I suggest one or the other, preferably cjs as packemon will automatically create an mjs wrapper. https://packemon.dev/docs/features#automatic-mjs-wrappers-for-cjs-inputs

[milesj]

Published, let me know if there's still issues.

[azu]

Thanks! 2022年7月28日(木) 7:50 Miles Johnson ***@***.***>:

…

Closed #133 <#133> as completed. — Reply to this email directly, view it on GitHub <#133 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAE2AUWXYLQMVAE4NZL5X3VWG4KRANCNFSM53XBQKKQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>

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[azu]

I want to treat my package as mjs package by default(type: module) because We may need to migrate Pure ESM in the future. I think that commonjs support is optional.
In other words, I want to treat .ts as mjs.

By contrast, index-wrapper.mjs force type: "commonjs". so it treat my pacakge as cjs package by default.

[milesj]

@azu How does the index-wrapper.mjs force it to CJS?

[azu]

@milesj
Reproduce repo: https://github.com/azu/packemon-cjs-and-mjs-wrapper

Reproduce Steps:

1. change type to "module" manually
2. npm run build
3. packemon will change type to "commonjs"

Aug-01-2022.07-21-05_optimized.mp4

[milesj]

@azu The type is set based on the chosen format: https://github.com/milesj/packemon/blob/master/packages/packemon/src/Package.ts#L475 And since the format is cjs, it sets it.

It shouldn't matter though since the wrapper will be used when importing from ESM because the import exports is set in exports.