Use of extensionAlias fails resolution of subpath exports in exports fields

[raviqqe]

Problem

When the extensionAlias option is set to resolve TypeScript files (e.g. { ".js": [".ts", ".js"] },) enhanced-resolve tries to resolve subpath exports of external packages using the .ts file extension first and fails without trying the .js file extension.

Impact

This prevents the use of Webpack in projects that enables ES modules and TypeScript and uses external packages with subpath exports in their exports fields.

Error message

> npm run build

> webpack-exports-extension-alias@1.0.0 build
> webpack

assets by status 872 bytes [cached] 5 assets
./src/index.ts 43 bytes [built] [code generated]

ERROR in ./src/index.ts 1:0-42
Module not found: Error: Package path ./string.ts is not exported from package /Users/raviqqe/src/github.com/raviqqe/til/webpack-exports-extension-alias/node_modules/@raviqqe/hidash (see exports field in /Users/raviqqe/src/github.com/raviqqe/til/webpack-exports-extension-alias/node_modules/@raviqqe/hidash/package.json)

webpack 5.80.0 compiled with 1 error in 606 ms

package.json in an example external package:

{
  "name": "@raviqqe/hidash",
  "version": "1.4.7",
  "description": "Yet another extension to Lodash",
  "repository": "https://github.com/raviqqe/hidash",
  "type": "module",
  "typesVersions": {
    "*": {
      "*": [
        "dist/*"
      ]
    }
  },
  "exports": {
    "./*.js": {
      "types": "./dist/*.d.ts",
      "default": "./dist/*.js"
    },
    "./promise.js": {
      "types": "./dist/promise.d.ts",
      "default": "./dist/promise.js"
    },
    "./stream.js": {
      "types": "./dist/stream.d.ts",
      "default": "./dist/stream.js"
    },
    "./string.js": {
      "types": "./dist/string.d.ts",
      "default": "./dist/string.js"
    }
  },
  "scripts": {
    // ...
  },
  "devDependencies": {
    // ...
  }
}

Minimal reproducible example

• Repository: https://github.com/raviqqe/til/tree/main/webpack-exports-extension-alias

Environment

• enhanced-resolve: 5.13.0
• webpack: 5.80.0
• ts-loader: 9.4.2
• Node.js: 20.0.0

Notes

Is this caused by the plugin order in the ResolverFactory?

[alexander-akait]

Expected, exports should provide ts files, spec cleary says that everything that is not in exports should not be resolved

[alexander-akait]

Duplicate of #355