Use `package.json#exports` map

[mischnic]

🙋 feature request

Use exports maps in the resolver

https://nodejs.org/api/esm.html#esm_package_exports
https://nodejs.org/api/esm.html#esm_conditional_exports
https://webpack.js.org/guides/package-exports/

💻 Examples

https://github.com/preactjs/preact/blob/master/package.json#L11
https://unpkg.com/browse/nanoid@3.1.18/package.json

Relevant code

The resolver: https://github.com/parcel-bundler/parcel/blob/v2/packages/resolvers/default/src/DefaultResolver.js
which calls: https://github.com/parcel-bundler/parcel/blob/v2/packages/utils/node-resolver-core/src/NodeResolver.js

[phaux]

Also, conditional exports could be used while bundling to specify the dist paths. They could replace package.json#{main,module,browser} if the package.json#exports key exists.

Example:

{
  "exports": {
    ".": {
      "require": "./dist/node/index.js",
      "import": "./dist/module/index.js",
      "browser": "./dist/browser/index.js"
    }
  }
}

Would be the same as:

{
  "main": "./dist/node/index.js",
  "module": "./dist/module/index.js",
  "browser": "./dist/browser/index.js",
}

[hybrist]

If nodejs/node#32869 lands, this likely should include support for NODE_ENV based resolution ("production" and "development").

[developit]

Some links to implementations/details in other tools/bundlers (more to come):

• Webpack
• Rollup
• Vite
• Snowpack
• WMR

[mischnic]

https://github.com/lukeed/resolve.exports might be useful

[rsthn]

This would be actually awesome! I was recently refactoring code and used the "exports" field, and I didn't know parcel didn't support this.