Bug: subpaths for lib format are not generated properly

[j3tan]

I noticed that in one of our packages, subpaths were not being built properly for lib format. ESM seems to work fine. This is highlighted by the fact that the generated exports file paths do not exist in the lib/ folder.

Package JSON example

{
 ...
  "packemon": [
    {
      "format": "esm",
      "platform": "browser",
      "inputs": {
        "index": "src/index.ts",
        "helpers": "src/helpers/index.ts",
        "utils": "src/utils/index.ts"
      }
    },
    {
      "format": "lib",
      "platform": "node",
      "inputs": {
        "index": "src/index.ts",
        "helpers": "src/helpers/index.ts",
        "utils": "src/utils/index.ts"
      }
    }
  ],
  "packageManager": "yarn@3.4.1",
  "types": "./lib/index.d.ts",
  "module": "./esm/index.js",
  "exports": {
    "./package.json": "./package.json",
    ".": {
      "browser": {
        "types": "./esm/index.d.ts",
        "module": "./esm/index.js",
        "import": "./esm/index.js"
      },
      "node": {
        "types": "./lib/index.d.ts",
        "default": "./lib/index.js"
      },
      "default": "./lib/index.js"
    },
    "./helpers": {
      "browser": {
        "types": "./esm/helpers.d.ts",
        "module": "./esm/helpers.js",
        "import": "./esm/helpers.js"
      },
      "node": {
        "types": "./lib/helpers.d.ts", <------ These do not exist
        "default": "./lib/helpers.js" <------ These do not exist 
      },
      "default": "./lib/helpers.js"
    },
    "./utils": {
      "browser": {
        "types": "./esm/utils.d.ts",
        "module": "./esm/utils.js",
        "import": "./esm/utils.js"
      },
      "node": {
        "types": "./lib/utils.d.ts", <------ These do not exist
        "default": "./lib/utils.js" <------ These do not exist
      },
      "default": "./lib/utils.js"
    }
  }
}

Example Repo:
https://github.com/j3tan/packemon-test/tree/main

Let me know if I'm missing a configuration or some important detail

[j3tan]

[milesj]

@j3tan It looks like esm code is being bundled, while lib is 1:1 file structure? If so, let me dig into the branching logic.

[j3tan]

@milesj Yes, exactly, the lib looks to be 1:1 while the other formats provide top-level files for subpath exports

[milesj]

@j3tan Dope, I believe this fixes it #185 I also noticed the ESM types were also wrong.

Can you verify before I merge?

[j3tan]

@milesj Looks like the fix works! Thanks!