Develop Reference

How to include external dependencies in UMD bundle with rollup

I'm using rollup to bundle a library and I want to include external dependencies together with my code in the UMD bundle. I can't find any useful information about this in the docs. It could be that I'm missing something obvious but it seems like the docs only demonstrates how to mark relative modules as external. I've been trying to achieve this without any success. Is it doable and if yes, how?
My code making use of an external component: src/index.ts
import { ExternalComponent } from 'external-component'
function MyComponent() {
const externalComponent = ExternalComponent()
// ...
}
export default MyComponent
Desired output: bundle.umd.js
function ExternalComponent() {
// ...
}
function MyComponent() {
const externalComponent = ExternalComponent()
// ...
}
rollup.config.js
import babel from '#rollup/plugin-babel'
import typescript from 'rollup-plugin-typescript2'
import resolve from '#rollup/plugin-node-resolve'
import { terser } from 'rollup-plugin-terser'
import localTypescript from 'typescript'
const CONFIG_BABEL = {
extensions: ['.js', '.jsx', '.ts', '.tsx'],
exclude: 'node_modules/**',
babelHelpers: 'bundled',
}
const CONFIG_TYPESCRIPT = {
tsconfig: 'tsconfig.json',
typescript: localTypescript,
}
const kebabCaseToPascalCase = (string = '') => {
return string.replace(/(^\w|-\w)/g, (replaceString) =>
replaceString.replace(/-/, '').toUpperCase(),
)
}
export default [
{
input: 'src/index.ts',
output: [
{
file: `${packageJson.name}.umd.js`,
format: 'umd',
strict: true,
sourcemap: false,
name: kebabCaseToPascalCase(packageJson.name),
plugins: [terser()],
}
],
plugins: [resolve(), typescript(CONFIG_TYPESCRIPT), babel(CONFIG_BABEL)],
},
]
package.json
{
"types": "index.d.ts",
"scripts": {
"build": "rollup -c",
"start": "rollup -c --watch",
},
"devDependencies": {
"#babel/core": "7.17.0",
"#rollup/plugin-babel": "^5.3.0",
"#rollup/plugin-node-resolve": "13.1.3",
"husky": "^4.3.8",
"npm-run-all": "^4.1.5",
"prettier": "2.5.1",
"rollup": "^2.67.0",
"rollup-plugin-terser": "^7.0.2",
"rollup-plugin-typescript2": "^0.31.2",
"typescript": "^4.5.5"
},
}
Thanks in advance,
David

I find something from the rollup documentation:
If you do want to include the module in your bundle, you need to tell Rollup how to find it. In most cases, this is a question of using #rollup/plugin-node-resolve.
But the #rollup/plugin-node-resolve doc does not help.

Webpack 5 React component library UMD bundle with SourceMaps

I am attempting to make a webpack 5 build process to create a react component library I just had a couple of things cannot seem to get working.
#1) The webpack build command works fine, and when using the inline-source-map option I can
SEE the data URL embeded in the outputted build file but when I ever I attempt to publish and test this library on NPM I always get obfuscated errors without original lines of code so I can't even tell where the errors are; what else am I missing to activate source-maps? I am using Chrome dev tools and it doesn't even tell me a source map is available for that code...
#2) Another issue I am having is after building this with webpack into the dist folder; I start another CRA test app and try to pull components out of the built library but all I get are these errors.
./src/dist/index.js
Line 1:1: Expected an assignment or function call and instead saw an expression no-unused-expressions
Line 1:112: 'define' is not defined no-undef
Line 1:123: 'define' is not defined no-undef
Line 1:190: Unexpected use of 'self' no-restricted-globals
Line 1:466: Expected an assignment or function call and instead saw an expression no-unused-expressions
Line 1:631: Expected an assignment or function call and instead saw an expression no-unused-expressions
I am aware webpack 5 stopped bundling polyfills for Node but shouldn't this code run
if I place it in the src directory of a CRA application? This is bundled code shouldn't it work in the browser/ in another React application? I targeted UMD so I thought it would work in this environment
here is all the necessary info
Webpack.config.js
const path = require("path");
const { CleanWebpackPlugin } = require("clean-webpack-plugin");
const nodeExternals = require("webpack-node-externals");
module.exports = {
entry: "./src/index.js",
devtool: "inline-source-map",
externals: [nodeExternals()],
output: {
filename: "index.js",
path: path.resolve(__dirname, "dist"),
library: {
name: "test",
type: "umd",
},
},
plugins: [new CleanWebpackPlugin()],
module: {
rules: [
{
test: /\.(js|jsx)$/,
exclude: /node_modules/,
use: {
loader: "babel-loader",
options: {
presets: ["#babel/preset-env", "#babel/preset-react"],
},
},
},
{
test: /\.scss$/,
use: ["style-loader", "css-loader", "sass-loader"],
include: path.resolve(__dirname, "./src"),
},
],
},
};
Package.json
{
"name": "test-lib",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "start-storybook",
"build": "webpack --mode production"
},
"keywords": [],
"author": "",
"license": "ISC",
"dependencies": {
"prop-types": "^15.7.2",
"react": "^17.0.2",
"react-dom": "^17.0.2"
},
"devDependencies": {
"#babel/core": "^7.15.8",
"#babel/preset-env": "^7.15.8",
"#babel/preset-react": "^7.14.5",
"#storybook/addon-knobs": "^6.3.1",
"#storybook/react": "^6.3.10",
"babel-loader": "^8.2.2",
"clean-webpack-plugin": "^4.0.0",
"node-sass": "^6.0.1",
"path": "^0.12.7",
"sass-loader": "^12.1.0",
"webpack": "^5.58.0",
"webpack-cli": "^4.9.0",
"webpack-node-externals": "^3.0.0"
}
}
Button.js (sample component)
import React from 'react'
import PropTypes from 'prop-types';
const Button = ({message = 'Hello world'}) => (
<button>{message}</button>
)
Button.propTypes = {
message: PropTypes.string.isRequired
}
export default Button
Build entry point (index.js)
export { default as Button } from "./components/Button";

Svelte 3: Could not import modules when unit testing

I'm trying to test a Svelte component with Jest. This component works fine in the browser, but unit test fails with importing modules.
For example, when running Jest, import uuid from 'uuid' compiled as const { default: uuid } = require("uuid");, and calling uuid.v4() causes TypeError: Cannot read property 'v4' of undefined. When I use import * as uuid from 'uuid' or const uuid = require('uuid'), Jest unit test passes, but it doesn't work in the browser.
How can I deal with this issue? Any information would greatly help. Thank you.
package.json:
{
"name": "svelte-app",
"version": "1.0.0",
"scripts": {
"build": "rollup -c",
"dev": "rollup -c -w",
"start": "firebase serve --only hosting"
},
"devDependencies": {
"#rollup/plugin-json": "^4.0.0",
"#testing-library/jest-dom": "^5.1.1",
"#testing-library/svelte": "^1.11.0",
"bulma": "^0.8.0",
"eslint": "^6.7.0",
"eslint-config-standard": "^14.1.0",
"eslint-plugin-import": "^2.18.2",
"eslint-plugin-jest": "^23.0.4",
"eslint-plugin-node": "^10.0.0",
"eslint-plugin-promise": "^4.2.1",
"eslint-plugin-standard": "^4.0.1",
"eslint-plugin-svelte3": "^2.7.3",
"jest-transform-svelte": "^2.1.1",
"node-sass": "^4.13.1",
"rollup": "^1.12.0",
"rollup-jest": "0.0.2",
"rollup-plugin-commonjs": "^10.0.0",
"rollup-plugin-livereload": "^1.0.0",
"rollup-plugin-node-builtins": "^2.1.2",
"rollup-plugin-node-globals": "^1.4.0",
"rollup-plugin-node-resolve": "^5.2.0",
"rollup-plugin-svelte": "^5.0.3",
"rollup-plugin-terser": "^5.1.2",
"sirv-cli": "^0.4.5",
"svelma": "^0.3.2",
"svelte": "^3.18.2",
"svelte-preprocess": "^3.4.0"
},
"dependencies": {
"firebase": "^7.8.2"
},
"private": true
}
rollup.config.js
import json from '#rollup/plugin-json'
import commonjs from 'rollup-plugin-commonjs'
import builtins from 'rollup-plugin-node-builtins'
import globals from 'rollup-plugin-node-globals'
import livereload from 'rollup-plugin-livereload'
import resolve from 'rollup-plugin-node-resolve'
import svelte from 'rollup-plugin-svelte'
import { terser } from 'rollup-plugin-terser'
import preprocess from 'svelte-preprocess'
const production = !process.env.ROLLUP_WATCH
export default {
input: 'src/main.js',
output: {
sourcemap: true,
format: 'iife',
name: 'app',
file: 'public/build/bundle.js',
},
plugins: [
// https://github.com/rollup/plugins/tree/master/packages/json
json(),
svelte({
// enable run-time checks when not in production
dev: !production,
// we'll extract any component CSS out into
// a separate file — better for performance
css: css => {
css.write('public/build/bundle.css')
},
preprocess: preprocess(),
}),
// If you have external dependencies installed from
// npm, you'll most likely need these plugins. In
// some cases you'll need additional configuration —
// consult the documentation for details:
// https://github.com/rollup/rollup-plugin-commonjs
resolve({
browser: true,
dedupe: importee => importee === 'svelte' || importee.startsWith('svelte/'),
}),
commonjs(),
globals(),
builtins(),
// In dev mode, call `npm run start` once
// the bundle has been generated
!production && serve(),
// Watch the `public` directory and refresh the
// browser on changes when not in production
!production && livereload('public'),
// If we're building for production (npm run build
// instead of npm run dev), minify
production && terser(),
],
watch: {
clearScreen: false,
},
}
function serve () {
let started = false
return {
writeBundle () {
if (!started) {
started = true
require('child_process').spawn('npm', ['run', 'start'], {
stdio: ['ignore', 'inherit', 'inherit'],
shell: true,
})
}
},
}
}
jest.config.js
const sveltePreprocess = require('svelte-preprocess')
module.exports = {
displayName: { name: 'web', color: 'magentaBright' },
moduleFileExtensions: [
'js',
'json',
'svelte',
],
preset: 'rollup-jest',
transform: {
'\\.js$': 'rollup-jest',
'\\.svelte$': ['jest-transform-svelte', { preprocess: sveltePreprocess(), debug: true }],
},
setupFilesAfterEnv: ['#testing-library/jest-dom/extend-expect'],
}

It worked for me.
The issue seems like jest unable to resolve uuid while building the code at runtime.
Which is quite obvious because by default jest ignore node_modules packages.
I faced similar issues and resolved it. The approach is by configuration inform JEST that it has to include node_modules packages as well. In my project i used rollup-plugin-babel.
This is the babel plugin configuration
...
...
babel({
extensions: [ '.js', '.mjs', '.html', '.svelte' ],
runtimeHelpers: true,
exclude: [ 'node_modules/#babel/**', 'node_modules/core-js/**' ],
presets: [
[
'#babel/preset-env',
{
targets: '> 0.25%, not dead',
useBuiltIns: 'usage',
corejs: 3
}
]
]
})
And I've added babel-jest for transforming the jest.config.js
module.exports = {
preset: 'jest-puppeteer', //ignore the preset part, I used for puppeteer
transform: {
'^.+\\.js?$': require.resolve('babel-jest'),
"^.+\\.ts?$": "ts-jest" // this part is only required if you have typescript project
}
};
DO Not forget to install this packages like babel-jest, rollup-plugin-babel before using it.

I have been facing this same issue and have a work around by mocking the module in the test file and giving it a default key.
jest.mock('uuid', () => ({
default: {
v4: jest.fn(),
},
}))
Another way that seems to work is to destructure the import in the component file.
import { v4 as uuidv4 } from 'uuid'

Self answer:
Finally, I wrote a little preprocessor to replace import foo from 'foo' -> import * as foo from 'foo'
svelteJestPreprocessor.js
const svelteJestPreprocessor = () => ({
// replace `import foo from 'foo'` -> `import * as foo from 'foo'`
script: ({ content }) => ({
// process each line of code
code: content.split('\n').map(line =>
// pass: no import, import with {}, import svelte component
(!line.match(/\s*import/)) || (line.match(/{/)) || (line.match(/\.svelte/)) ? line
: line.replace(/import/, 'import * as'),
).join('\n'),
}),
})
module.exports = svelteJestPreprocessor
jest.config.js
const svelteJestPreprocessor = require('./svelteJestPreprocessor')
const sveltePreprocess = require('svelte-preprocess')
module.exports = {
moduleFileExtensions: [
'js',
'json',
'svelte',
],
preset: 'rollup-jest',
transform: {
'\\.js$': 'rollup-jest',
'\\.svelte$': ['jest-transform-svelte', {
preprocess: [
svelteJestPreprocessor(),
sveltePreprocess(),
],
}],
},
setupFilesAfterEnv: ['#testing-library/jest-dom/extend-expect'],
}
This is an unwanted workaround, but it works for now.

webpack imported module is not a constructor

I created a small JS module which I intend to make an npm package, but for now is just on GitHub. This module is written in ES6 and SCSS, and is thus relying on webpack and babel for transpilation.
To test it, I created a separate project with a similar setup (webpack and babel). After npm installing my module, when trying to import it into my index.js, I get the following error in Chrome Developer Tools: (with x being my module's name)
index.js:11 Uncaught TypeError: x__WEBPACK_IMPORTED_MODULE_1___default.a is not a constructor
at eval (index.js:11)
at Object../src/index.js (main.js:368)
at __webpack_require__ (main.js:20)
at eval (webpack:///multi_(:8081/webpack)-dev-server/client?:2:18)
at Object.0 (main.js:390)
at __webpack_require__ (main.js:20)
at main.js:69
at main.js:72
I've looked through countless answers and tried countless solutions, to no avail. My module's setup is as follows.
.babelrc
{
"presets": [
["env", {
"targets": {
"browsers": ["ie >= 11"]
}
}]
],
"plugins": [
"transform-es2015-modules-commonjs",
"transform-class-properties"
]
}
webpack.common.js
const path = require('path')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const cleanWebpackPlugin = require('clean-webpack-plugin')
const baseSCSS = new ExtractTextPlugin('main/_base.css')
const themeSCSS = new ExtractTextPlugin('main/_theme.css')
module.exports = {
entry: {
example: [
path.join(__dirname, 'src', 'example', 'index.js')
],
main: [
'idempotent-babel-polyfill',
path.join(__dirname, 'src', 'index.js')
]
},
output: {
path: path.join(__dirname, 'dist'),
filename: path.join('[name]', 'index.js')
},
module: {
rules: [
{
test: /\.js$/,
exclude: /node_modules/,
use: {
loader: 'babel-loader',
}
},
{
test: /\.scss$/,
use: ExtractTextPlugin.extract(
{
fallback: 'style-loader',
use: ['css-loader', 'sass-loader']
}
)
},
{
test: /\_base-scss$/,
use: baseSCSS.extract(
{
fallback: 'style-loader',
use: ['css-loader', 'sass-loader']
}
)
},
{
test: /\_theme-scss$/,
use: themeSCSS.extract(
{
fallback: 'style-loader',
use: ['css-loader', 'sass-loader']
}
)
}
]
},
plugins: [
new cleanWebpackPlugin('dist', {}),
new ExtractTextPlugin({ filename: path.join('example', 'style.css') }),
baseSCSS,
themeSCSS,
new HtmlWebpackPlugin({
inject: false,
hash: true,
template: path.join(__dirname, 'src', 'example', 'index.html'),
filename: path.join('example', 'index.html')
})
]
}
webpack.prod.js
const merge = require('webpack-merge')
const UglifyJSPlugin = require('uglifyjs-webpack-plugin')
const webpack = require('webpack')
const common = require('./webpack.common.js')
module.exports = merge(common, {
plugins: [
new UglifyJSPlugin({
sourceMap: true
}),
new webpack.DefinePlugin({
'process.env.NODE_ENV': JSON.stringify('production')
})
],
mode: 'production'
})
package.json
{
"name": "my-module-name",
"version": "1.0.0-beta.1",
"description": "",
"main": "dist/main/index.js",
"scripts": {
"start": "webpack-dev-server --config webpack.dev.js",
"server": "node src/server",
"format": "prettier-standard 'src/**/*.js'",
"lint": "eslint src",
"build": "webpack --config webpack.prod.js",
"test": "echo \"Error: no test specified\" && exit 1"
},
"author": "Liran",
"license": "ISC",
"devDependencies": {
"babel-core": "^6.26.0",
"babel-eslint": "^8.2.3",
"babel-loader": "^7.1.4",
"babel-plugin-transform-class-properties": "^6.24.1",
"babel-plugin-transform-es2015-modules-commonjs": "^6.26.2",
"babel-preset-env": "^1.7.0",
"clean-webpack-plugin": "^0.1.19",
"css-loader": "^0.28.11",
"eslint": "^4.19.1",
"extract-text-webpack-plugin": "^4.0.0-beta.0",
"html-webpack-plugin": "^3.2.0",
"idempotent-babel-polyfill": "^0.1.1",
"node-sass": "^4.9.0",
"prettier-standard": "^8.0.1",
"sass-loader": "^7.0.1",
"style-loader": "^0.21.0",
"uglifyjs-webpack-plugin": "^1.2.5",
"webpack": "^4.6.0",
"webpack-cli": "^2.0.15",
"webpack-dev-middleware": "^3.1.3",
"webpack-dev-server": "^3.1.3",
"webpack-merge": "^4.1.2"
}
}
Any help/pointers would be greatly appreciated. If you need more information, please let me know.

If you are not the library author and are having a problem consuming another library, you may be seeing an error like this:
TypeError: [LIBRARY_NAME]__WEBPACK_IMPORTED_MODULE_3__ is not a constructor
If that's the case, you may be importing the library incorrectly in your code (it may be a problem with default exports). Double check the library docs for usage.
It may be as simple as changing this:
import Foo from 'some-library/Foo';
to this:
import { Foo } from 'some-library';

It is not working because it is missing libraryTarget and library properties. By doing that webpack know which format of module you would like to create, i.e: commonjs (module.exports) or es (export).
I would do something like:
...
output: {
path: path.join(__dirname, 'dist'),
filename: path.join('[name]', 'index.js'),
library: "my-library",
libraryTarget: "umd" // exposes and know when to use module.exports or exports.
},
...

Besides setting the libraryTarget, it may also be necessary to move the export in the JavaScript file to the default.
function MyClassName() {
...
}
export default MyClassName;
And then in the webpack configuration the library type umd ...
(Note that I have used the newer library.type instead the older libraryTarget (see https://webpack.js.org/configuration/output/#outputlibrarytarget).
const path = require('path');
module.exports = {
mode: "production",
entry: '../wherever/MyClassName.js',
output: {
library: {
name: "MyClassName",
type: "umd", // see https://webpack.js.org/configuration/output/#outputlibrarytype
export: "default", // see https://github.com/webpack/webpack/issues/8480
},
filename: 'MyClassName.min.js',
path: path.resolve(__dirname, '../wherever/target/')
},
optimization: {
minimize: true
}
};
The export default makes the class available in JavaScript like the file was embedded directly, i.e.,
<script type="text/javascript" src="MyClassName.min.js"></script>
<script type="text/javascript">
<!--
var myInstance = new MyClassName();
// -->
</script>
Disclaimer: I added this answer even though the original question is three years old by now. After encountering the "is not a constructor" issue, it took me hours of searching to find the default solution. And that was the second time, I searched and found it :D

Cf. David Calhoun's answer, if you run into this with a third-party library, you may be trying to import a CommonJS module as an ECMAScript module. The workaround there seems to be to use require instead of import, e.g., instead of
import { Foo } from 'bar'
you need to write
const Foo = require('bar')
(There may be a more elegant way to handle this, but this is what worked for me.)

For me, it was the cache issue. Just cleared the cookies, cache data and closed, reopened the browser. It worked.

In my case, the error was being caused in React when trying to invoke JS's built-in Error constructor, or in other words, basically when calling throw new Error("something").
On inspection of my code, I realised I had a component called Error in my project which was being imported into the same file. The name clash between this component and JS's built-in Error constructor was causing the error mentioned in the question.

In case something is using wepack 5 + babel 7
"webpack": "5.73.0",
"#babel/core": "7.4.4",
"#babel/preset-env": "7.4.4",
"babel-loader": "8.0.5",
AND want to use class instead function, this worked for me:
class Person {
constructor(fname, lname, age, address) {
this.fname = fname;
this.lname = lname;
this.age = age;
this.address = address;
}
get fullname() {
return this.fname +"-"+this.lname;
}
}
export default Person;
In my case .babelrc was not necesary

tl;dr
Make sure that you import properly through index files.
Explanation
For me, this error was caused by importing through index files. I had multiple directories with their index.ts files that exported all the files inside the directory. These index files were accumulated/reexported by a main index.ts file so everything can be imported through it.
src/
├── index.ts
├── module1/
│ ├── index.ts
│ ├── file1.ts
│ └── file2.ts
└── module2/
├── index.ts
├── file3.ts
└── file4.ts
In file4.ts I had an import like this:
import { file1Class, file2Class, file3Class } from "src";
I had to split it into two separate imports:
import { file1Class, file2Class } from "src/module1";
import { file3Class } from "src/module2";

ReactJS linting (eslint) and transpiling (babel) error on shared code using monorepo (Lerna + Yarn Workspaces)

I´m building a monorepo using yarn workspaces, lerna and 2 different projects:
ux - a React component library built using create-react-app
auth - a React application that uses ux library built using create-react-app and then ejected (the ejection was done to try to solve the current linting and transpiling error).
My monorepo setup is:
project
|-------- node_modules
|-------- lerna.json
|-------- package.json
|-------- packages
|----------- auth
|------- node_modules
|------- src
|------- packages.json
|----------- ux
|------- node_modules
|------- src
|------- packages.json
lerna.json:
{
"lerna": "2.9.0",
"npmClient": "yarn",
"useWorkspaces": true,
"packages": [
"packages/*"
],
"version": "3.0.0"
}
Lerna root package.json:
{
"name": "myorganization",
"version": "3.0.0",
"license": "UNLICENSED",
"workspaces": ["packages/*"],
"private": true,
"scripts": {
"clean": "lerna clean -f --yes && rm -rf node_modules",
"reset": "yarn run clean && yarn",
"auth": "cd packages/auth && yarn start"
},
"devDependencies": {
"lerna": "^2.9.0"
}
}
ux package.json: (ux was not ejected)
{
"name": "#myorganization/ux",
"version": "3.0.0",
"author": "Me",
"private": true,
"license": "UNLICENSED",
"dependencies": {
"react": "^16.2.0",
"react-dom": "^16.2.0",
"react-scripts": "2.0.0-next.9754a231"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test --env=jsdom",
"eject": "react-scripts eject"
},
"browserslist": {
"development": [
"last 2 chrome versions",
"last 2 firefox versions",
"last 2 edge versions"
],
"production": [
">1%",
"last 4 versions",
"Firefox ESR",
"not ie < 11"
]
},
"devDependencies": {
"eslint": "^4.19.0",
"eslint-plugin-react": "^7.7.0"
}
}
auth package.json:
{
"name": "#myorganization/auth",
"version": "3.0.0",
"private": true,
"author": "Me",
"license": "UNLICENSED",
"dependencies": {
"#myorganization/ux": "^3.0.0",
"#babel/core": "7.0.0-beta.38",
"#babel/runtime": "7.0.0-beta.38",
"autoprefixer": "7.2.5",
"babel-core": "7.0.0-bridge.0",
"babel-eslint": "8.2.1",
"babel-jest": "22.1.0",
"babel-loader": "8.0.0-beta.0",
"babel-preset-react-app": "4.0.0-next.9754a231",
"case-sensitive-paths-webpack-plugin": "2.1.1",
"chalk": "2.3.0",
"css-loader": "0.28.9",
"dotenv": "4.0.0",
"dotenv-expand": "4.0.1",
"eslint-config-react-app": "3.0.0-next.9754a231",
"eslint-loader": "1.9.0",
"eslint-plugin-flowtype": "2.41.0",
"eslint-plugin-import": "2.8.0",
"eslint-plugin-jsx-a11y": "6.0.3",
"extract-text-webpack-plugin": "3.0.2",
"file-loader": "1.1.6",
"fs-extra": "5.0.0",
"html-webpack-plugin": "2.30.1",
"identity-obj-proxy": "3.0.0",
"jest": "22.1.2",
"object-assign": "4.1.1",
"postcss-flexbugs-fixes": "3.2.0",
"postcss-loader": "2.0.10",
"promise": "8.0.1",
"raf": "3.4.0",
"react": "^16.2.0",
"react-dev-utils": "6.0.0-next.9754a231",
"react-dom": "^16.2.0",
"react-router-dom": "^4.2.2",
"style-loader": "0.19.1",
"svgr": "1.6.0",
"sw-precache-webpack-plugin": "0.11.4",
"thread-loader": "1.1.2",
"uglifyjs-webpack-plugin": "1.1.6",
"url-loader": "0.6.2",
"webpack": "3.10.0",
"webpack-dev-server": "2.11.0",
"webpack-manifest-plugin": "1.3.2",
"whatwg-fetch": "2.0.3"
},
"scripts": {
"start": "node scripts/start.js",
"build": "node scripts/build.js",
"test": "node scripts/test.js --env=jsdom"
},
"browserslist": {
"development": [
"last 2 chrome versions",
"last 2 firefox versions",
"last 2 edge versions"
],
"production": [
">1%",
"last 4 versions",
"Firefox ESR",
"not ie < 11"
]
},
"jest": {
"collectCoverageFrom": [
"src/**/*.{js,jsx,mjs}"
],
"setupFiles": [
"<rootDir>/config/polyfills.js"
],
"testMatch": [
"<rootDir>/src/**/__tests__/**/*.{js,jsx,mjs}",
"<rootDir>/src/**/?(*.)(spec|test).{js,jsx,mjs}"
],
"testEnvironment": "node",
"testURL": "http://localhost",
"transform": {
"^.+\\.(js|jsx|mjs)$": "<rootDir>/node_modules/babel-jest",
"^.+\\.css$": "<rootDir>/config/jest/cssTransform.js",
"^(?!.*\\.(js|jsx|mjs|css|json)$)": "<rootDir>/config/jest/fileTransform.js"
},
"transformIgnorePatterns": [
"'[/\\\\]node_modules[/\\\\](?!' + paths.allLernaModules.join('|') + ').*\\.(js|jsx|mjs)$'",
"^.+\\.module\\.css$"
],
"moduleNameMapper": {
"^react-native$": "react-native-web",
"^.+\\.module\\.css$": "identity-obj-proxy"
},
"moduleFileExtensions": [
"web.js",
"mjs",
"js",
"json",
"web.jsx",
"jsx",
"node"
]
},
"babel": {
"presets": [
"react-app"
]
},
"eslintConfig": {
"extends": "react-app"
},
"devDependencies": {
"eslint": "^4.19.0",
"eslint-plugin-react": "^7.7.0"
}
}
Then I´ve changed the create-react-app created config/paths to grab the referenced packages:
"use strict";
const path = require("path");
const fs = require("fs");
const url = require("url");
// Make sure any symlinks in the project folder are resolved:
// https://github.com/facebookincubator/create-react-app/issues/637
const appDirectory = fs.realpathSync(process.cwd());
const resolveApp = relativePath => path.resolve(appDirectory, relativePath);
const envPublicUrl = process.env.PUBLIC_URL;
function ensureSlash(path, needsSlash) {
const hasSlash = path.endsWith("/");
if (hasSlash && !needsSlash) {
return path.substr(path, path.length - 1);
} else if (!hasSlash && needsSlash) {
return `${path}/`;
} else {
return path;
}
}
const getPublicUrl = appPackageJson =>
envPublicUrl || require(appPackageJson).homepage;
// We use `PUBLIC_URL` environment variable or "homepage" field to infer
// "public path" at which the app is served.
// Webpack needs to know it to put the right <script> hrefs into HTML even in
// single-page apps that may serve index.html for nested URLs like /todos/42.
// We can't use a relative path in HTML because we don't want to load something
// like /todos/42/static/js/bundle.7289d.js. We have to know the root.
function getServedPath(appPackageJson) {
const publicUrl = getPublicUrl(appPackageJson);
const servedUrl =
envPublicUrl || (publicUrl ? url.parse(publicUrl).pathname : "/");
return ensureSlash(servedUrl, true);
}
// config after eject: we're in ./config/
module.exports = {
dotenv: resolveApp(".env"),
appPath: resolveApp("."),
appBuild: resolveApp("build"),
appPublic: resolveApp("public"),
appHtml: resolveApp("public/index.html"),
appIndexJs: resolveApp("src/index.js"),
appPackageJson: resolveApp("package.json"),
appSrc: resolveApp("src"),
yarnLockFile: resolveApp("yarn.lock"),
testsSetup: resolveApp("src/setupTests.js"),
appNodeModules: resolveApp("node_modules"),
publicUrl: getPublicUrl(resolveApp("package.json")),
servedPath: getServedPath(resolveApp("package.json"))
};
module.exports.lernaRoot = path
.resolve(resolveApp("."), "../")
.endsWith("packages")
? path.resolve(resolveApp("."), "../../")
: resolveApp(".");
module.exports.appLernaModules = [];
module.exports.appLernaNodeModules = path.join(
module.exports.lernaRoot,
"node_modules"
);
fs.readdirSync(module.exports.appLernaNodeModules).forEach(folderName => {
if (folderName === "react-scripts") return;
if (folderName.substr(0, 1) === ".") return;
let fullName = path.join(module.exports.appLernaNodeModules, folderName);
if (folderName.substr(0, 1) === "#" && fs.lstatSync(fullName).isDirectory()) {
fs.readdirSync(fullName).forEach(subFolderName => {
let subFullName = path.join(fullName, subFolderName);
if (fs.lstatSync(subFullName).isSymbolicLink()) {
let src = fs.realpathSync(subFullName);
module.exports.appLernaModules.push(src);
}
});
}
if (fs.lstatSync(fullName).isSymbolicLink()) {
module.exports.appLernaModules.push(fs.realpathSync(fullName));
}
});
And changed the create-react-app original webpack.config.dev to:
"use strict";
const autoprefixer = require("autoprefixer");
const path = require("path");
const webpack = require("webpack");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const CaseSensitivePathsPlugin = require("case-sensitive-paths-webpack-plugin");
const InterpolateHtmlPlugin = require("react-dev-utils/InterpolateHtmlPlugin");
const WatchMissingNodeModulesPlugin = require("react-dev-utils/WatchMissingNodeModulesPlugin");
const eslintFormatter = require("react-dev-utils/eslintFormatter");
const ModuleScopePlugin = require("react-dev-utils/ModuleScopePlugin");
const getClientEnvironment = require("./env");
const paths = require("./paths");
// Webpack uses `publicPath` to determine where the app is being served from.
// In development, we always serve from the root. This makes config easier.
const publicPath = "/";
// `publicUrl` is just like `publicPath`, but we will provide it to our app
// as %PUBLIC_URL% in `index.html` and `process.env.PUBLIC_URL` in JavaScript.
// Omit trailing slash as %PUBLIC_PATH%/xyz looks better than %PUBLIC_PATH%xyz.
const publicUrl = "";
// Get environment variables to inject into our app.
const env = getClientEnvironment(publicUrl);
// Options for PostCSS as we reference these options twice
// Adds vendor prefixing based on your specified browser support in
// package.json
const postCSSLoaderOptions = {
// Necessary for external CSS imports to work
// https://github.com/facebookincubator/create-react-app/issues/2677
ident: "postcss",
plugins: () => [
require("postcss-flexbugs-fixes"),
autoprefixer({
flexbox: "no-2009"
})
]
};
console.log(paths.appLernaModules.concat(paths.appSrc));
// This is the development configuration.
// It is focused on developer experience and fast rebuilds.
// The production configuration is different and lives in a separate file.
module.exports = {
// You may want 'eval' instead if you prefer to see the compiled output in DevTools.
// See the discussion in https://github.com/facebookincubator/create-react-app/issues/343.
devtool: "cheap-module-source-map",
// These are the "entry points" to our application.
// This means they will be the "root" imports that are included in JS bundle.
// The first two entry points enable "hot" CSS and auto-refreshes for JS.
entry: [
// We ship a few polyfills by default:
require.resolve("./polyfills"),
// Include an alternative client for WebpackDevServer. A client's job is to
// connect to WebpackDevServer by a socket and get notified about changes.
// When you save a file, the client will either apply hot updates (in case
// of CSS changes), or refresh the page (in case of JS changes). When you
// make a syntax error, this client will display a syntax error overlay.
// Note: instead of the default WebpackDevServer client, we use a custom one
// to bring better experience for Create React App users. You can replace
// the line below with these two lines if you prefer the stock client:
// require.resolve('webpack-dev-server/client') + '?/',
// require.resolve('webpack/hot/dev-server'),
require.resolve("react-dev-utils/webpackHotDevClient"),
// Finally, this is your app's code:
paths.appIndexJs
// We include the app code last so that if there is a runtime error during
// initialization, it doesn't blow up the WebpackDevServer client, and
// changing JS code would still trigger a refresh.
],
output: {
// Add /* filename */ comments to generated require()s in the output.
pathinfo: true,
// This does not produce a real file. It's just the virtual path that is
// served by WebpackDevServer in development. This is the JS bundle
// containing code from all our entry points, and the Webpack runtime.
filename: "static/js/bundle.js",
// There are also additional JS chunk files if you use code splitting.
chunkFilename: "static/js/[name].chunk.js",
// This is the URL that app is served from. We use "/" in development.
publicPath: publicPath,
// Point sourcemap entries to original disk location (format as URL on Windows)
devtoolModuleFilenameTemplate: info =>
path.resolve(info.absoluteResourcePath).replace(/\\/g, "/")
},
resolve: {
// This allows you to set a fallback for where Webpack should look for modules.
// We placed these paths second because we want `node_modules` to "win"
// if there are any conflicts. This matches Node resolution mechanism.
// https://github.com/facebookincubator/create-react-app/issues/253
modules: ["node_modules", paths.appNodeModules].concat(
// It is guaranteed to exist because we tweak it in `env.js`
process.env.NODE_PATH.split(path.delimiter).filter(Boolean)
),
// These are the reasonable defaults supported by the Node ecosystem.
// We also include JSX as a common component filename extension to support
// some tools, although we do not recommend using it, see:
// https://github.com/facebookincubator/create-react-app/issues/290
// `web` extension prefixes have been added for better support
// for React Native Web.
extensions: [".web.js", ".mjs", ".js", ".json", ".web.jsx", ".jsx"],
alias: {
// Support React Native Web
// https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
"react-native": "react-native-web"
},
plugins: [
// Prevents users from importing files from outside of src/ (or node_modules/).
// This often causes confusion because we only process files within src/ with babel.
// To fix this, we prevent you from importing files out of src/ -- if you'd like to,
// please link the files into your node_modules/ and let module-resolution kick in.
// Make sure your source files are compiled, as they will not be processed in any way.
new ModuleScopePlugin(paths.appSrc, [paths.appPackageJson])
]
},
module: {
strictExportPresence: true,
rules: [
// Disable require.ensure as it's not a standard language feature.
{ parser: { requireEnsure: false } },
// First, run the linter.
// It's important to do this before Babel processes the JS.
{
test: /\.(js|jsx|mjs)$/,
enforce: "pre",
use: [
{
options: {
formatter: eslintFormatter,
eslintPath: require.resolve("eslint")
},
loader: require.resolve("eslint-loader")
}
],
include: paths.appLernaModules.concat(paths.appSrc)
},
{
// "oneOf" will traverse all following loaders until one will
// match the requirements. When no loader matches it will fall
// back to the "file" loader at the end of the loader list.
oneOf: [
// "url" loader works like "file" loader except that it embeds assets
// smaller than specified limit in bytes as data URLs to avoid requests.
// A missing `test` is equivalent to a match.
{
test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
loader: require.resolve("url-loader"),
options: {
limit: 10000,
name: "static/media/[name].[hash:8].[ext]"
}
},
// Process application JS with Babel.
// The preset includes JSX, Flow, and some ESnext features.
{
test: /\.(js|jsx|mjs)$/,
include: paths.appLernaModules.concat(paths.appSrc),
use: [
// This loader parallelizes code compilation, it is optional but
// improves compile time on larger projects
require.resolve("thread-loader"),
{
loader: require.resolve("babel-loader"),
options: {
// This is a feature of `babel-loader` for webpack (not Babel itself).
// It enables caching results in ./node_modules/.cache/babel-loader/
// directory for faster rebuilds.
cacheDirectory: true,
highlightCode: true
}
}
]
},
// Process any JS outside of the app with Babel.
// Unlike the application JS, we only compile the standard ES features.
{
test: /\.js$/,
use: [
// This loader parallelizes code compilation, it is optional but
// improves compile time on larger projects
require.resolve("thread-loader"),
{
loader: require.resolve("babel-loader"),
options: {
babelrc: false,
compact: false,
presets: [
require.resolve("babel-preset-react-app/dependencies")
],
cacheDirectory: true,
highlightCode: true
}
}
]
},
// "postcss" loader applies autoprefixer to our CSS.
// "css" loader resolves paths in CSS and adds assets as dependencies.
// "style" loader turns CSS into JS modules that inject <style> tags.
// In production, we use a plugin to extract that CSS to a file, but
// in development "style" loader enables hot editing of CSS.
// By default we support CSS Modules with the extension .module.css
{
test: /\.css$/,
exclude: /\.module\.css$/,
use: [
require.resolve("style-loader"),
{
loader: require.resolve("css-loader"),
options: {
importLoaders: 1
}
},
{
loader: require.resolve("postcss-loader"),
options: postCSSLoaderOptions
}
]
},
// Adds support for CSS Modules (https://github.com/css-modules/css-modules)
// using the extension .module.css
{
test: /\.module\.css$/,
use: [
require.resolve("style-loader"),
{
loader: require.resolve("css-loader"),
options: {
importLoaders: 1,
modules: true,
localIdentName: "[path]__[name]___[local]"
}
},
{
loader: require.resolve("postcss-loader"),
options: postCSSLoaderOptions
}
]
},
// Allows you to use two kinds of imports for SVG:
// import logoUrl from './logo.svg'; gives you the URL.
// import { ReactComponent as Logo } from './logo.svg'; gives you a component.
{
test: /\.svg$/,
use: [
{
loader: require.resolve("babel-loader"),
options: {
cacheDirectory: true
}
},
require.resolve("svgr/webpack"),
{
loader: require.resolve("file-loader"),
options: {
name: "static/media/[name].[hash:8].[ext]"
}
}
]
},
// "file" loader makes sure those assets get served by WebpackDevServer.
// When you `import` an asset, you get its (virtual) filename.
// In production, they would get copied to the `build` folder.
// This loader doesn't use a "test" so it will catch all modules
// that fall through the other loaders.
{
// Exclude `js` files to keep "css" loader working as it injects
// its runtime that would otherwise be processed through "file" loader.
// Also exclude `html` and `json` extensions so they get processed
// by webpacks internal loaders.
exclude: [/\.(js|jsx|mjs)$/, /\.html$/, /\.json$/],
loader: require.resolve("file-loader"),
options: {
name: "static/media/[name].[hash:8].[ext]"
}
}
]
}
// ** STOP ** Are you adding a new loader?
// Make sure to add the new loader(s) before the "file" loader.
]
},
plugins: [
// Makes some environment variables available in index.html.
// The public URL is available as %PUBLIC_URL% in index.html, e.g.:
// <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
// In development, this will be an empty string.
new InterpolateHtmlPlugin(env.raw),
// Generates an `index.html` file with the <script> injected.
new HtmlWebpackPlugin({
inject: true,
template: paths.appHtml
}),
// Add module names to factory functions so they appear in browser profiler.
new webpack.NamedModulesPlugin(),
// Makes some environment variables available to the JS code, for example:
// if (process.env.NODE_ENV === 'development') { ... }. See `./env.js`.
new webpack.DefinePlugin(env.stringified),
// This is necessary to emit hot updates (currently CSS only):
new webpack.HotModuleReplacementPlugin(),
// Watcher doesn't work well if you mistype casing in a path so we use
// a plugin that prints an error when you attempt to do this.
// See https://github.com/facebookincubator/create-react-app/issues/240
new CaseSensitivePathsPlugin(),
// If you require a missing module and then `npm install` it, you still have
// to restart the development server for Webpack to discover it. This plugin
// makes the discovery automatic so you don't have to restart.
// See https://github.com/facebookincubator/create-react-app/issues/186
new WatchMissingNodeModulesPlugin(paths.appNodeModules),
// Moment.js is an extremely popular library that bundles large locale files
// by default due to how Webpack interprets its code. This is a practical
// solution that requires the user to opt into importing specific locales.
// https://github.com/jmblog/how-to-optimize-momentjs-with-webpack
// You can remove this if you don't use Moment.js:
new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/)
],
// Some libraries import Node modules but don't use them in the browser.
// Tell Webpack to provide empty mocks for them so importing them works.
node: {
dgram: "empty",
fs: "empty",
net: "empty",
tls: "empty",
child_process: "empty"
},
// Turn off performance hints during development because we don't do any
// splitting or minification in interest of speed. These warnings become
// cumbersome.
performance: {
hints: false
}
};
OBS: Repair the console.log() command in the code above to show what is being loaded.
Running, I´m getting the following result:
$ npm start
> #myorganization/auth#3.0.0 start D:\project\packages\auth
> node scripts/start.js
[ 'D:\\project\\packages\\auth',
'D:\\project\\packages\\ux',
'D:\\project\\packages\\auth\\src' ]
Starting the development server...
Failed to compile.
../ux/src/atoms/index.js
Module build failed: Error: No ESLint configuration found.
Commenting the eslint step in webpack.config.dev, I´m getting:
$ npm start
> #myorganization/auth#3.0.0 start D:\project\packages\auth
> node scripts/start.js
[ 'D:\\project\\packages\\auth',
'D:\\project\\packages\\ux',
'D:\\project\\packages\\auth\\src' ]
Starting the development server...
Failed to compile.
../ux/src/atoms/ActivityItem/ActivityItem.js
Syntax error: D:\project\packages\ux\src\atoms\ActivityItem\ActivityItem.js: Support for the experimental syntax 'classProperties' isn't currently enabled (34:20):
32 | class ActivityItem extends Component {
33 |
> 34 | static propTypes = {
| ^
35 | showHeader: PropTypes.bool,
36 | timestamp: PropTypes.number,
37 | username: PropTypes.string,
Add #babel/plugin-proposal-class-properties (https://git.io/vb4SL) to the 'plugins' section of your Babel config to enable transformation.
In short, the shared code is not being either transpiled or linted, and that breaks the whole project. The whole project was done using ES6.

As of react-scripts 2.0 they removed support for monorepos (https://github.com/facebook/create-react-app/issues/1333). However if you scroll to the bottom of the issues page you will see a link to react-workspaces. I've not tried it, but it looks promising. (https://github.com/react-workspaces/react-workspaces-playground)