Show that an "exports" alias in package.json can be used to point the import root of a Node.js package to a subfolder (f.e. dist/).

Run the example with Node.js v13.2 or higher:

node .

The output is:

$ node .
(node:73031) ExperimentalWarning: The ESM module loader is experimental.
Bar
Lorem
Foo

See node_modules/test-package.

More detailed explantation

Some projects compile TypeScript, CoffeeScript, or other source code in a src/ folder into final output in a dist/ folder, but they may not want consumers of their package to have to include the dist/ folder in any import statements.

A package author can achieve this with an exports configuration in their package.json like so:

{
	"name": "some-package",
	"type": "module",
	"exports": {
		".": "./dist/index.js",
		"./": "./dist/"
	}
}

which allows end users to import things relative to the package root instead of the dist folder:

import {...} from 'some-package'
// loads some-package/dist/index.js

import {...} from 'some-package/subfolder/foo.js'
// loads some-package/dist/subfolder/foo.js

Related issue: nodejs/node#14970