Consuming pure ES2015 libraries with Webpack 2 - ecmascript-6

Question

Context
I've been using a monolithic src tree internally and have recently split it into separate smaller libraries for reuse. Since this is all internal, I have no need for these libraries to produce ES5. I want our webpack 2 apps to be able to consume pure ES2015 libraries.
Problem
The problem is, when I produce a pure ES2015 library, my webpack transpiled app fails with:
Uncaught TypeError: Class constructor RouteConfig cannot be invoked without 'new'
The source of this is:
import {RouteConfig} from '#acme/ui/config'
Sanity check
For verification that I'm not doing anything obviously wrong, I verified:
the library built as ES5 works
the app including the library (with the ES2015 preset added to it) via source alias works
Details
Library .babelrc
{ // produce a pure es2015 build
"presets": [
"es2017",
"es2016",
"stage-0",
"react"
],
"plugins": [
"babel-relay-plugin-loader",
"flow-react-proptypes",
"transform-flow-strip-types",
"lodash",
"transform-runtime"
],
"env": {
"production": {
"presets": [
"react-optimize"
],
"plugins": [
["react-remove-properties", {"properties": ["data-test"]}]
]
}
}
}
Application .babelrc:
{
"presets": [
"es2017",
"es2016",
["es2015", {"modules": false}], // allows webpack2 to interpret ES2015 modules+
"stage-0", // if omitted, this leaves `export Log from './Log'`
"react"
],
"plugins": [
"babel-relay-plugin-loader",
"flow-react-proptypes",
"transform-flow-strip-types",
"lodash",
"transform-runtime",
"react-hot-loader/babel"
],
"env": {
"production": {
"presets": [
"react-optimize"
],
"plugins": [
["react-remove-properties", {"properties": ["data-test"]}]
]
}
}
}
TLDR;
We have many libraries and many apps that are internal and don't need ES5
I want to author both a library and an app in ES2015+.
Each library will create a pure ES2015 build for the private npm package.
I want to take advantage of as much webpack 2 tree shaking/optimization as possible.
Our library works as an ES5 package
Our library works as a source alias to the app with the 2015 preset added to it's .babelrc
Source alias usage for all our libraries is not desirable
Question
What config is needed to get webpack 2 to consume a pure ES2015 library?

Answer 1

It's possible you're excluding the node_modules folder in your babel-loader. If so, you can try modifying the exclude regex.
ie.
test: /\.js$/,
use: [
'babel-loader'
],
exclude: [/.*node_modules((?!folder_name_here).)*$/]