Develop Reference

import css file into es6 returns string instead of object

TL;DR
I'm importing a css file into a typescript module, but the import resolves to a string instead of an object. Can anyone tell me why I don't get an object??
Example
// preview.ts
import test from './src/assets/test.theme.css';
// also tried this:
// import * as test from './src/assets/test.theme.css';
console.log('typeof test: ', typeof test);
console.log(test);
Console output
Detailed explanation
Actually, I'm trying to set up a Storybook for my Angular12 component library.
In order to provide various themes, I want to use the #etchteam/storybook-addon-css-variables-theme plugin, which in its documentation refers to the inline loader syntax of Webpack.
import myTheme from '!!style-loader?injectType=lazyStyleTag!css-loader!./assets/my-theme.css';
When applying this to my code my browser console started to complain
Error: myTheme.use is not a function
During my research I recognized that the imported stylesheet is not an evaluated javascript object, but instead it is provided as a string containing the sourcecode generated by the style-loader.
I also recognized, that this issue is not specific to the style-loader, but also occurs for all other loaders, e.g. css-loader, raw-loader, etc.
This issue is also not related to inline loader syntax, as it also shows up with loaders being defined in a minimalistic webpack config.
Environment:
Angular 12
Webpack 5
Reproduction
I have set up a GIT repo reproducing the issue.
The readme file explains the repro and the issue.

I think you have mistake in your Webpack config. You have nested rules property, instead you should have use:
{
rules: [
{
test: /\.css$/i,
use: ["style-loader", "css-loader"],
},
],
}
https://webpack.js.org/loaders/css-loader/

I'm sorry, but I have to revert my last statement. My issue has NOT been resolved by #Akxe's comment.
Now my import statement (import * as test from '...') resolves to an object, but it's still not correct.
I have set up a GIT Repo to reproduce the issue. The readme.md file explains the repro and the issue.
It looks like Webpack is not executing/evaluating the return value of the loader.
Btw. this is not just the case with the css-loader. The result stays the same for raw-loader, sass-loader, style-loader, etc.
My final goal is to lazily load my theme files into a storybook.
I try to follow the documentation of the #etchteam/storybook-addon-css-variables-> theme.

Finally I got my issue solved!
Analysis
The main issue here is the webpack configuration generated by the #angular-devkit/build-angular package. I was able to analyze it by debugging a fresh angular12 application (you can check it out here).
By setting a break-point at /node_modules/#angular-devkit/build-angular/src/utils/webpack-browser-config.js, function: generateWebpackConfig(...), I could inspect the final webpackConfig object in the debugger.
The relevant rule looks like this:
The important part here is the rule setting the module type to asset/source, instructing webpack not to evaluate the loader's result.
Solution concept 1: inline loader
With the help of alexander-kait and his great hints at this issue,
I was able to find an inline-loader syntax that overrides webpack's module declaration:
import Test from 'test.css.webpack[javascript/auto]!=!!!style-loader?injectType=lazyStyleTag!css-loader!./test.css';
console.log(typeof Test); // output: object
console.log(Test); // output: Object { use: () => void, unuse: () => void }
Test.use(); // this should usually be called by a theme switcher...
I'm not really sure about the url pattern here, as it seems to be an undocumented feature, but I assume that it's something like <query-pattern>.webpack[<module-type>]!=!<loaders><query>.
However, since this is an undocumented feature, I was rather reluctant to use it.
Solution concept 2: webpackConfig customization
Since I'm in a storybook context, I decided to customize the webpack configuration according to the storybook documentation.
My solution requires to set up a naming convention (e.g. *.theme.css).
// .storybook/main.js
module.exports = {
webpackFinal: async (config) => {
// exclude *.theme.css from the *.css ruleset
config.module.rules.find(rule => '.css'.match(rule.test)).exclude = [ /\.(?:theme\.css)$/i ];
// add a rule for *.theme.css
config.module.rules.push({
test: /\.(?:theme\.css)$/i,
use: [
{ loader: 'style-loader', options: { injectType: 'lazyStyleTag' } },
'css-loader',
],
});
},
};
With these rules in place, I can now simply do the following:
// preview.js
import LightTheme from './light.theme.css';
import DarkTheme from './dark.theme.css';
setupThemeSwitcher(LightTheme, DarkTheme);
Please note that the setupThemeSwitcher function is just pseudocode merely there for the example. In reality I'm using the #etchteam/storybook-addon-css-variables-theme addon...

I had a very similar issue with storybook and this extension, except l’m loading .scss files.
I simply adapted solution 2 to suit my .scss case and it works like a charm.
I couldn’t make solution 1 to work, but as stated, it sounds hacky whereas solution 2 is cleaner in my opinion.
Thanks a lot for sharing this solution, I was struggling for hours.

How to use CodeMirror runmode standalone version in a webpack setup

I'm using CodeMirror as a simple syntax highlighter (≠ code editor) with the runmode addon. In order to save some bandwidth to users, i want to switch to runmode-standlone.js version, which is also included in the package but doesn't bring the whole CodeMirror power and weight attached.
The problem, as referenced by the library author is that CodeMirror library is listed as dependency of each mode (the lang packages):
you have to somehow convince your bundler to load the runmode-standalone shim instead of the regular core library for that dependency. — Author
Anyone managed to do this?
What i've already tried
Note, i've setup an alias so when i reference codemirror, it imports the standalone version (just FYI, because i've also tried without it)
// webpack.config.js
resolve: {
alias: {
codemirror$: path.resolve(__dirname, "node_modules/codemirror/addon/runmode/runmode-standalone.js")
}
}
All combinations of script-loader, imports-loader to try to execute mode modules as normal scripts
import "codemirror";
// same as import "codemirror/addon/runmode/runmode-standalone.js";
// nope
import "script-loader!codemirror/mode/javascript/javascript";
// nope
import "imports-loader?define=>false!codemirror/mode/javascript/javascript";
// nope
import "imports-loader?define=>false,module=>false,require=>false!codemirror/mode/javascript/javascript";
A similar strategy to what's suggested for ignoring moment.js locales (repo, SO thread, using webpackIgnorePlugin
// codemirror/mode/javascript/javascript.js import looks like
(function(mod) {
if (typeof exports == "object" && typeof module == "object") // CommonJS
mod(require("../../lib/codemirror"));
else if (typeof define == "function" && define.amd) // AMD
define(["../../lib/codemirror"], mod);
else // Plain browser env
mod(CodeMirror);
})(function(CodeMirror) {
...
So i've tried to make it ignore
new webpack.IgnorePlugin({
resourceRegExp: /^\.\.\/lib\/codemirror$/,
contextRegExp: /^codemirror\/mode\/(.*)/
});
Setup details
Using codemirror#5.47.0 and webpack#4.29.6

Configure webpack to use externals.
The externals configuration option provides a way of excluding dependencies from the output bundles. Instead, the created bundle relies on that dependency to be present in the consumer's (any end-user application) environment.
externals: {
'../lib/codemirror': 'CodeMirror', // for mode/meta.js
'../../lib/codemirror': 'CodeMirror' // for mode/[mode]/[mode].js
}

'Subject' is not exported by rxjs in rollup.js

I am trying to set up my project to use rollup, as part of an angular2 move to AOT compilation, however, I am getting the following issue.
Error: 'Subject' is not exported by node_modules\rxjs\Subject.js
This is my rollup.js file:
import rollup from 'rollup';
import nodeResolve from 'rollup-plugin-node-resolve'
import commonjs from 'rollup-plugin-commonjs';
import uglify from 'rollup-plugin-uglify'
export default {
entry: 'client/main.js',
dest: 'public/assets/js/build.js',
sourceMap: false,
format: 'iife',
plugins: [
nodeResolve({jsnext: true, module: true}),
commonjs({
include: 'node_modules/rxjs/**',
include: 'node_modules/angular2-jwt/**',
}),
uglify()
]
}
Why is this happening, I have followed the angular2 cookbook guide?

You'll need to use the namedExports option with rollup-plugin-commonjs: https://github.com/rollup/rollup-plugin-commonjs#custom-named-exports.
Also, you may find it useful to include: 'node_modules/**' rather than individual packages, as otherwise any dependencies of your dependencies will bypass the plugin (in the config above, you have duplicate include properties – perhaps that's just a typo? If you need to pass multiple values, use an array).
commonjs({
include: 'node_modules/**',
namedExports: {
'node_modules/rxjs/Subject.js': [ 'Subject' ]
}
})

I finally figured this out on my system.
The named export solution is wrong since rollup-plugin-commonjs will handle the exports in Subject.js just fine.
The problem for me was the "includes" option in rollup-plugin-commonjs.
There are two issues.
Number one: when specifying the includes in the options as "node_modules/rxjs/**" you have to be sure the full path resolves to where you expect it to.
Example:
I run my build command from "c:/foo/build" but my files are in "c:/my-source" then the include patterns might resolve to "c:/build/node_modules" which means when the commonjs plugin is checking if it should handle "node_modules/rxjs/" it will see that "c:/my-source/node_modules/rxjs/" does not match "c:/build/node_modules/rxjs/**" thus it will not convert the exports to ES6.
The second issue is case sensitivity. The include patterns are case sensitive. This tripped me up too.
Both of these issues can be confirmed by opening the "node_modules\rollup-plugin-commonjs\dist\rollup-plugin-commonjs.cjs.js" file and debugging the "transform" function.
If you modify the code (at the very beginning of the transform function) to be something like this
if (id.includes('rxjs\\Subject.js')) {
debugger;
}
and then run the code in a debugger, you can step through the code until it gets to the filter function. There you will see the filter function is skipping the "rxjs/Subject.js" file.
I almost guarantee this is the problem when the error occurs.

I have found that this can happen in combination with symlinks.

Path aliases for imports in WebStorm

I use webpack path aliases for ES6 module loading.
E.g. If I define an alias for utils instead of something like
import Foo from "../../../utils/foo", I can do
import Foo from "utils/foo"
The problem is that once I start using aliases, WebStorm looses track of the import and I'm left with warnings and no auto-completion.
Is there a way to instruct WebStorm to use such aliases?

Yes, there is.
In fact, Webstorm can't automatically parse and apply Webpack config, but you can set up aliases the same way.
You just have to mark the parent folder of "utils" (in your example) as a resource root (right-click, mark directory as / resource root).
We just managed to do with the following structure :
/src
/A
/B
/C
We have A B and C folders declared as alias in Webpack.
And in Webstorm we marked "src" as "Resource Root".
And now we can simply import :
import A/path/to/any/file.js
instead of
import ../../../../../A/path/to/any/file.js
while still having Webstorm correctly parsing and indexing all code, link to files, autocompleting and so on ...

I managed to set up aliases for WebStorm 2017.2 within webpack like this:

For the record: in PHPSTORM, working with laravel mix, I managed to solve this by creating a webpack.config.js file separately like:
const path = require('path')
const webpack = require('webpack')
module.exports = {
...
resolve: {
extensions: ['.js', '.json', '.vue'],
alias: {
'~': path.resolve(__dirname, './resources/assets/js')
}
},
...
}
And then importing it in the webpack.mix.js like:
const config = require('./webpack.config')
...
mix.webpackConfig(config)
Make sure the webpack configuration file is pointed correctly in the configuration of the PhpStorm in: Settings > Languages & Frameworks > Javascript > Webpack

You can define custom paths, so WebStorm/PhpStorm can understand your aliases. But make sure, they are identical with your aliases. Create file in your root directory and call it something like this: webStorm.config.js (any js file will be ok). Then configure your paths inside:
System.config({
"paths": {
"components/*": "./src/components/*",
"core/*": "./src/core/*",
...
}
});
WebStorm/PhpStorm will recognize System as it's own module and will treat this file as configuration.

This is answered in a comment but to save people digging into comments and link only information, here it is:
As of WS2017.2 this will be done automatically. The information is here.
According to this, webstorm will automatically resolve aliases that are included within the webpack.config in the root of the project. If you have a custom structure and your webpack.config isn't in the root folder then go to Settings | Languages & Frameworks | JavaScript | Webpack and set the option to the config you require.
Note: Most setups have a base config which then call a dev or prod version. In order for this to work properly, you need to tell webstorm to use the dev one.

Not right now, We were also using path aliases for the files in our react project. The import names were shorter but we lost a lot on static checking of webstorm as well as completion features.
We later came up with a decision to reduce the code to only 3 levels of depth, as well a single level for the common parts. The path completion feature of webstom (ctrl + space) even helps reduce the typing overhead. The production build does not use longer names, so hardly makes any difference in final code.
I will suggest please reconsider your decision about aliases. You loose semantic meaning of modules coming from node_modules and your own code, as well as referencing the alias files again and again to make sense of your code, is a much bigger overhead.

add jsconfig.js on your project root
{
"compilerOptions": {
"baseUrl": ".",
"paths": {
"~/*": ["./src/*"]
}
}
}

In PHPStorm (using 2017.2 currently), I have not been able to get webpack configs to work properly in regards to aliases.
My fix involves using the "Directories" section of the main settings. I just had to mark each folder referenced by an alias as a sources root, then click the properties dropdown for each and specify the alias as a "Package prefix". This made everything link up for me.
Not sure if the Directories section exists in WebStorm, but if it does, this seems to be a fool-proof method for getting import aliases working.

For anyone struggling: path.resolve() must be called with "__dirname" first argument for Idea (Websorm) to be able to resolve the path correctly.
Will work for Idea (Websorm):
alias: {
'#someAlias': pathLib.resolve(__dirname, 'path/to/directory')
}
Will not work for Idea (Websorm) (while still being valid webpack alias):
alias: {
'#someAlias': pathLib.resolve('path/to/directory')
}

Webstorm can't read webpack.config if module.exports return a function.
For example
module.exports = function (webpackEnv) {
return {
mode: isEnvProduction ? 'production' : isEnvDevelopment && 'development',
...
}
}
Check your config file, maybe this cause you are a problem.

There is a lot of discussion here about Laravel Mix, so I'll leave this here to help out future readers. I solved this by creating a separate (fake) webpack config file which is only used by my IDE (PHPStorm).
1. Create a separate alias.js file (e.g. /webpack/alias.js)
const path = require('path');
const assets = path.join(__dirname,'..','resources','assets');
module.exports = {
'#js' : path.resolve(assets, 'js'),
'#c' : path.resolve(assets, 'js', 'components'),
'#errors' : path.resolve(assets, 'js', 'errors'),
'#utils' : path.resolve(assets, 'js', 'utils'),
'#store' : path.resolve(assets, 'js', 'store'),
'#api' : path.resolve(assets, 'js', 'api'),
'#less' : path.resolve(assets, 'less')
}
2. Require the alias.js file into webpack.mix.js
const mix = require('laravel-mix');
mix.alias(require('./webpack/alias'))
// ... The rest of your mix, e.g.
.js('app.js')
.vue()
.less('app.less');
3. Create the fake webpack config for your IDE (e.g. /webpack/ide.config.js)
Here, import the laravel-mix webpack config, plus your aliases, and any other config that the IDE might need help finding. Also include the prefixed ~ aliases for importing styles into your Vue components.
/*
|--------------------------------------------------------------------------
| A fake config file for PhpStorm to enable aliases
|--------------------------------------------------------------------------
|
| File > Settings... > Languages & Frameworks > Javascript > Webpack
|
| Select "Manually" and set the configuration file to this
|
*/
const path = require('path');
const mixConfig = require('./../node_modules/laravel-mix/setup/webpack.config')();
module.exports = {
...mixConfig,
resolve: {
alias: {
...require('./alias'),
'~#less' : path.resolve('#less'), // <--
},
...mixConfig.resolve
}
}
4. Set your IDE to use webpack/ide.config.js as your webpack config file.

Had the same problem on a new Laravel project with Jetstream. The webpack.config.js was present and correct. But PHPStorm still didn't recognize the # symbol as a resource root.
After opening the webpack config, I got a notification:
After Clicking on Trust project and run, the # symbol became recognized.
I know that this isn't the solution or use-case for everyone. But I still found it worthy to note on this post, because it helped me in my situation.
Using
laravel/framework:8.77.1
npm:8.3.0
node:v14.18.1

Using webpack with an existing requirejs application

I am working with an existing application (canvas-lms) that uses RequireJS in its build system. I'm working on a pseudo-standalone application that plugs into Canvas (a "client_app" in Canvas parlance). This is a fontend-only app that makes API calls back to the host Canvas app. The details aren't terribly important for my question - all a client_app needs to do is have a build script that spits out a JS file in a defined place within the Canvas app tree.
I'm trying to use Webpack to build my app instead of RequireJS. Everything works great if I keep all my dependencies self-contained (e.g. npm-install everything I need); however, Canvas already provides many of these dependencies (e.g. React, jQuery), and in jQuery's case, it provides a patched version that I'd like to use instead. This is where I start to have problems.
Getting React to work was easy; Canvas installs it with bower, so I was able to add an alias in my webpack config to point at it:
alias: {
'react': __dirname + '/vendor/canvas/public/javascripts/bower/react/react-with-addons',
}
(__dirname + /vendor/canvas is a symlink in my application tree to the host Canvas application's tree)
Where I'm having trouble is trying to load the provided copy of jQuery.
Canvas has the following jQuery structure:
/public/javascripts/jquery.js:
define(['jquery.instructure_jquery_patches'], function($) {
return $;
});
/public/javascripts/jquery.instructure_jquery_patches.js:
define(['vendor/jquery-1.7.2', 'vendor/jquery.cookie'], function($) {
// does a few things to patch jquery ...
// ...
return $;
});
/public/javascripts/vendor/jquery.cookie.js -- looks like the standard jquery.cookie plugin, wrapped in an AMD define:
define(['vendor/jquery-1.7.2'], function(jQuery) {
jQuery.cookie = function(name, value, options) {
//......
};
});
and finally, /public/javascripts/vendor/jquery-1.7.2.js. Not going to paste it in, since it's bog-standard jQuery1.7.2, except that the AMD define has been made anonymous -- reverting it to the stock behaviour doesn't make a difference.
I want to be able to do something like var $ = require('jquery') or import $ from 'jquery' and have webpack do whatever magic, poorly-documented voodoo it needs to do to use jquery.instructure-jquery-patches.
I've tried adding the path to resolve.root in my webpack.config.js file:
resolve: {
extensions: ['', '.js', '.jsx'],
root: [
__dirname + '/src/js',
__dirname + '/vendor/canvas/public/javascripts'
],
alias: {
'react': 'react/addons',
'react/addons/lib': 'react/../lib'
}
},
This should mean that when I do a require('jquery'), it first finds /public/javascripts/jquery.js, which defines a module with instructure_jquery_patches as a dependency. That falls into instructure_jquery_patches, which defines a module with two dependencies ('vendor/jquery-1.7.2', 'vendor/jquery.cookie').
In my main entry point (index.js), I am importing jQuery (also tried a commonjs require, no difference), and trying to use it:
import React from 'react';
import $ from 'jquery';
$('h1').addClass('foo');
if (__DEV__) {
require('../scss/main.scss');
window.React = window.React || React;
console.log('React: ', React.version);
console.log('jQuery:', $.fn.jquery);
}
Building the bundle with webpack seems to work; there are no errors. When I try to load the page in the browser, though, I'm getting an error from within jquery.instructure-jquery-patches.js:
It would seem that jQuery is not availble within jquery.instructure-jquery-patches.
It is, however, available in the global scope after the page loads, so jQuery is being evaluated and executed.
My guess is that I'm running into some sort of requirejs/amd asynchronicity problem, but that's a shot in the dark. I don't know enough about requirejs or amd to know for sure.

TobiasK's comment pointed me at needing to add amd: { jQuery: true } to my webpack config. Everything is working now.