ES6 example modules do not provide exports (in node)

Description of the problem

Following https://threejs.org/docs/#manual/en/introduction/Import-via-modules

import * as THREE from 'three';
import { STLLoader } from 'three/examples/jsm/loaders/STLLoader.js';

in an index.mjs for Node results in

import { STLLoader } from 'three/examples/jsm/loaders/STLLoader.js';
         ^^^^^^^^^^^^^
SyntaxError: The requested module 'three/examples/jsm/loaders/STLLoader.js' does not provide an export named 'STLLoader'

I know it’s node and not a browser - but some threejs features such as loaders are perfectly usable without display - and the NON-jsm version works perfect in my setup

require('three/examples/js/loaders/STLLoader.js');

BTW: same problem when copy-pasting the example from the website

import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js';

Three.js version

• r117

Browser

• node 12.18.0

OS

• macOS

Hardware Requirements (graphics card, VR Device, …)

[gkjohnson]

Such imports in node.js only work if the imported files are also mjs files, which is obviously not true for the npm package.

In the package.json you can actually specify that a package is of type module and node will automatically try to load everything as module, meaning you don’t have to specify the extension as mjs. They suggest denoting the “type” of the package whether it’s commonjs or module in order to future proof the package so it should probably be done anyway. You can see in the docs here.

Presumably this would mean that the file in the “main” field should be module rather than commonjs compatible (which we’re not doing) but I know has been discussed. At least I believe using "type" : "module" should enable everything to work when the user is explicitly importing the build/three.module.js file in their application.

[donmccurdy]

Recap — Node.js supports ES6 Modules in modern versions, but makes design choices that cause interoperability to be difficult for library authors who also need to support the web and backward-compatibility.

For three.js users, I’d suggest using esm as a workaround in Node.js.

For the three.js project, I think our current state is probably the best it can be under the circumstances. We cannot use "type": "json" in the root package.json because the source code is not entirely modules, and renaming things to .cjs or .mjs is not going to happen. Perhaps it would be possible to put {"type": "module"} into examples/jsm/package.json and just affect those files; if someone would like to test that with Node.js please do.

But with current Node.js support, and our current understanding of the problem, there doesn’t appear to be anything to do here. I’d vote to close this as well.