Programmatic Webpack & Jest (ESM): can't resolve module without '.js' file extension - node.js

Question

I'm using webpack programmatically, with typescript, ESM, and jest. In a jest test I'm getting errors for not including a .js file extension when importing ES modules. For example:
Module not found: Error: Can't resolve 'modulename' in '/path/components'
Did you mean 'modulename.js'?
BREAKING CHANGE: The request 'modulename' failed to resolve only because it was resolved as fully specified
(probably because the origin is strict EcmaScript Module, e. g. a module with javascript mimetype, a '*.mjs' file, or a '*.js' file where the package.json contains '"type": "module"').
The extension in the request is mandatory for it to be fully specified.
Add the extension to the request.
The module in question does indeed have "type": "module" set in its package.json. I have tried adding .js to the import, and it doesn't help.
I'm invoking jest with:
node --experimental-vm-modules --experimental-specifier-resolution=node node_modules/jest/bin/jest.js
as is recommended in the docs (everything else works except webpack). Note that I have tried with and without --experimental-specifier-resolution=node (this has helped in other similar circumstances).
Any thoughts on how to get webpack to work? Thanks in advance!
Note: everything was working until it was all converted to ESM! Now only programmatic webpack isn't working.
Webpack config:
{
entry,
target: 'web',
output: {
path: outputDir,
filename: '[name].js',
},
mode: process.env.NODE_ENV as 'development' | 'production' | 'none' | undefined,
resolve: {
extensions: [
'.ts',
'.tsx',
'.js',
'.jsx',
'.ttf',
'.eot',
'.otf',
'.svg',
'.png',
'.woff',
'.woff2',
'.css',
'.scss',
'.sass',
],
},
module: {
rules: [
{
test: /\.(ttf|eot|otf|svg|png)$/,
loader: 'file-loader',
},
{
test: /\.(woff|woff2)$/,
loader: 'url-loader',
},
{
test: /\.(js|jsx|ts|tsx)$/,
exclude: /node_modules/,
loader: 'babel-loader',
options: {
sourceType: 'unambiguous',
presets: [
[
'#babel/preset-env',
{
corejs: '3.0.0,',
useBuiltIns: 'usage',
},
],
'#babel/preset-react',
'#babel/preset-typescript',
],
plugins: [
'css-modules-transform',
[
'babel-plugin-react-scoped-css',
{
include: '.scoped.(sa|sc|c)ss$',
},
],
'#babel/plugin-proposal-class-properties',
],
},
},
{
test: /\.(sc|c|sa)ss$/,
use: [
'style-loader',
'css-loader',
'scoped-css-loader',
'sass-loader',
],
},
],
},
}

Answer 1

Ok so I found the solution here.
Basically, had to add 2 things to the webpack config under module.rules:
{
test: /\.m?js/,
type: "javascript/auto",
},
{
test: /\.m?js/,
resolve: {
fullySpecified: false,
},
},

Answer 2

#nerdlinger answer worked for me. I had this webpack.config.js
module.exports = {
entry: './src/index.js',
module: {
rules: [
{
test: /\.(js)$/,
exclude: /node_modules/,
use: {
loader: 'babel-loader'
}
}
],
}
...
}
and i changed it to this
module.exports = {
entry: './src/index.js',
module: {
rules: [
{
test: /\.(js)$/,
exclude: /node_modules/,
use: {
loader: 'babel-loader'
},
resolve: {
fullySpecified: false,
}
}
],
}
...
}