package.json exports array

[thdxr]

noticing that when i specify exports like this

  "exports": {
    "./*": [
      "./src/*/index.ts",
      "./src/*.ts"
    ]
  },

esbuild does not seem to find anything matching the second item - switching the order confirms that

any ideas?

[evanw]

The path resolution algorithm that esbuild implements for exports intentionally follows node's behavior. This is because node created and specified the algorithm for exports very precisely. Here's what node and esbuild both do for this:

$ cat index.mjs 
import foo from 'pkg/foo'
import bar from 'pkg/bar'
console.log({ foo, bar })

$ cat node_modules/pkg/package.json 
{
  "exports": {
    "./*": [
      "./src/*/index.js",
      "./src/*.js"
    ]
  }
}

$ cat node_modules/pkg/src/foo/index.js 
module.exports = 'foo'

$ cat node_modules/pkg/src/bar.js      
module.exports = 'bar'

$ node index.mjs
node:internal/errors:490
    ErrorCaptureStackTrace(err);
    ^

Error [ERR_MODULE_NOT_FOUND]: Cannot find module './node_modules/pkg/src/bar/index.js' imported from ./index.mjs
    at new NodeError (node:internal/errors:399:5)
    at finalizeResolution (node:internal/modules/esm/resolve:326:11)
    at moduleResolve (node:internal/modules/esm/resolve:945:10)
    at defaultResolve (node:internal/modules/esm/resolve:1153:11)
    at nextResolve (node:internal/modules/esm/loader:163:28)
    at ESMLoader.resolve (node:internal/modules/esm/loader:838:30)
    at ESMLoader.getModuleJob (node:internal/modules/esm/loader:424:18)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:77:40)
    at link (node:internal/modules/esm/module_job:76:36) {
  code: 'ERR_MODULE_NOT_FOUND'
}

Node.js v18.16.1

$ esbuild --bundle index.mjs
✘ [ERROR] Could not resolve "pkg/bar"

    index.mjs:2:16:
      2 │ import bar from 'pkg/bar'
        ╵                 ~~~~~~~~~

  The module "./src/bar/index.js" was not found on the file system:

    node_modules/pkg/package.json:4:6:
      4 │       "./src/*/index.js",
        ╵       ~~~~~~~~~~~~~~~~~~

  You can mark the path "pkg/bar" as external to exclude it from the bundle, which will remove this
  error and leave the unresolved path in the bundle.

1 error

As you can see, esbuild's behavior matches node's behavior, so I consider esbuild's behavior to be correct.

[evanw]

Closing as a duplicate of #2974.