Webpack Error Reading/Resolving the Entry Module - npm

I'm receiving an error when trying to execute a watch command on webpack and cannot figure out the problem. I have a feeling there's more than one issue, but I'm pretty sure I at least have an idea of one of the problems.
To give a little background, I'm way out of my know-how with all of this and am trying to self-teach how to write a web application with python. I stumbled onto this blog post with a basic example with detailed instructions:
https://codeburst.io/creating-a-full-stack-web-application-with-python-npm-webpack-and-react-8925800503d9
... and getting errors with no context from the source material. They also have a github and youtube video where it was presented, but still no such luck.
I think part of the issue is that their example was written on a MAC which the directory works a little different than windows which is my computer, so in part of the code the directory appears to be off because of that. Here's a screenshot showing the Node.js, the file folder, and the webpack.config.js code:
Here's a screenshot showing the Node.js, the file folder, and the webpack.config.js code:
I noticed that the directory in the example had had '/static/js/index.jsx', but my directory uses the other slash \static\js\index.jsx and the error shows the odd combining as C:\Users...\static/static/js/index.jsx. After learning that \ was an escape code in javascript, I eventually tried the code re-done with the changed slashes.
Here's another screenshot showing the newly run effect ... and it didn't appear to have an effect.
So I'm not sure if what I "fixed" was also an error, but not the current one since it doesn't make sense to me how directory slashes can change... but still no real answers and my knowledge on this was too thin to effectively look it up or learn the nature of the issue.
I have a feeling the actual module either is or may also have some kind of error in the webpack code, but I'm not too sure.
Thanks for any and all time on helping me out,
Matt
Edit: the original post had screenshots of the code and reference to the source material it was copied from, but for reference here are the code segments:
The directory layout is:
| Documents
|--- Python Scripts
|--- fullstacktemplate
|--- fullstack_template
|--- static
|--- js
|--- index.jsx
| node_modules
| index.html
| package.json
| package-lock.json
| webpack.config.js
The node_modules and package-lock.json were auto-created with set up of NPM, Webpack, and/or Babel. Package.json was further edited which will be listed below.
index.jsx is 1 line:
alert("Hello World!");
package.json is as follows:
{
"name": "fullstacktemplate",
"version": "1.0.0",
"description": "fullstack template that will say hello in another language when activated",
"main": "index.jsx",
"scripts": {
"build": "webpack -p --progress --config webpack.config.js",
"dev-build": "webpack --progress -d --config webpack.config.js",
"test": "echo \"Error: no test specified\" && exit 1",
"watch": "webpack --progress -d --config webpack.config.js --watch"
},
"keywords": [
"python",
"react",
"npm",
"webpack"
],
"author": "Matt Lane",
"license": "ISC",
"devDependencies": {
"webpack": "^4.28.2"
}
}
webpack.config.js is as follows:
const webpack = require('webpack');
const config = {
entry: __dirname + '\\js\\index.jsx',
output: {
path: __dirname + '\\dist',
filename: 'bundle.js',
},
resolve: {
extensions: ['.js', '.jsx', '.css']
},
module: {
rules: [
{
test: /\.jsx?/,
exclude: /node_modules/,
use: 'babel-loader'
}
]
}
};
module.exports = config;
The webpack.config.js file is my "corrected" one with the \ slashes. The original unedited version was:
const webpack = require('webpack');
const config = {
entry: __dirname + '/js/index.jsx',
output: {
path: __dirname + '/dist',
filename: 'bundle.js',
},
resolve: {
extensions: ['.js', '.jsx', '.css']
},
module: {
rules: [
{
test: /\.jsx?/,
exclude: /node_modules/,
use: 'babel-loader'
}
]
}
};
module.exports = config;

Related

run webpack as a postinstall npm script

I'm updating a private node_module that we install in projects via bitbucket. The package has some overrides that get bundled up via webpack and that bundle is used directly (i.e. outside of the build tools used for the project I'm installing the module for).
I would like to fire the module's build command as a postinstall script so that when we install or update the module in the main project the bundle is rebuilt.
In the module's package.json I have this:
"scripts": {
"build": "webpack",
"dev": "webpack --watch",
"serve": "webpack-dev-server",
"postinstall": "npm run build"
},
and I have the following webpack.config.js file:
const path = require("path")
module.exports = {
mode: "development",
watch: false,
entry: "./src/index.js",
output: {
filename: "bundle.js",
path: path.resolve(__dirname, "dist"),
},
devServer: {
contentBase: "dist",
},
module: {
rules: [
{
test: /\.js/,
exclude: /(node_modules)/,
use: {
loader: "babel-loader",
options: {
presets: ["#babel/preset-env"],
},
},
},
],
},
}
And I've confirmed that firing npm run build works just fine in the modules codebase, but when I go to update the module in the main codebase I get errors:
Webpack is blowing up on the option chaining which I thought would be handled by the babel loader in the module's webpack config.
I double checked my module's package.json file and it definitely has babel's presets in the regular dependencies and not the dev dependencies (i.e. it gets installed as part of the module install).
Am I doing something wrong here? It seems like if the same build process works
Make sure your exports in the package.json points to the sources in the dist:
"exports": {
".": "./dist/bundle.js"
},
https://nodejs.org/api/packages.html#package-entry-points

Vue - Compile other folder outside of /src in Vue.js project

I have a regular Vue.js project (created using v3.0.3) that uses WebSockets. Also in the project root is the /server folder which has the Node.js code that houses the multi-player aspect and socket code.
However, since the folder /server is independent of the /src folder from the Vue.js project, how do I make use of the Vue CLI webpack config and add babel compiling (using Webpack) to appropriately compile both the /src
https://cli.vuejs.org/guide/webpack.html#simple-configuration
I was able to import babel-cli and just compile/run like so:
./node_modules/.bin/nodemon --exec babel-node --presets env,stage-2 server.js
and it worked.
Actually, you should add .babelrc file and declare presets, env options and etc into it.
I don't know why you don't eject, because of access to webpack configuration. In the webpack config, you can declare your src folder or exclude other folders like node_modlules or your custom server folder.
For example, see webpack config for your issue:
module.exports = {
~~~
module: {
rules: [
{
test: /\.(js|jsx)$/,
exclude: ['node_modules', 'server'],
use: [
{
loader: 'babel-loader',
},
],
},
~~~
And see a sample .babelrc file:
{
"presets": [
"es2015",
"es2016",
"es2017",
"env",
"stage-0"
],
"plugins": [
"transform-class-properties",
"transform-object-rest-spread",
[
"transform-runtime",
{
"helpers": true,
"polyfill": true,
"regenerator": true
}
]
],
"env": {
"development": {
"compact": false
}
}
}
Then you should use your webpack commands to build:
webpack -p --config ./webpack.production.config.js

Vue Cli 3: defined output paths

I need to configure the output paths of the final build as described below:
My Vue project is default from structure but the output paths are outside this structure:
Output HTML file is: ../main/resources/
Output of all asset files: ../main/assets/[js/css/img]
And in the index.html file the path where to find the assets has to be "js/name.js" and similar.
My current vue.config.js does not provides this:
module.exports = {
chainWebpack: config => {
config.module
.rule('vue')
.use('vue-loader')
.tap(options => {
return options;
});
},
css: {
sourceMap: true
},
baseUrl: '/',
outputDir: '../main/resources/',
assetsDir: '../main/assets/',
runtimeCompiler: undefined,
productionSourceMap: undefined,
parallel: undefined,
configureWebpack: {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/,
use: [
{
loader: 'file-loader',
options: {
outputPath: '../main/assets/img',
name: '../main/assets/img/[name].[ext]'
}
}
]
}
]
}
}
}
Can someone help to configure this file? Thank you!
With kind regards
tschaefermedia
Sorry, I was busy with other projects. Now back to VueJS.
UPDATE:
I tried what was indicated in the GIT posts. My vue.config.js files looks now like this:
const path = require('path');
module.exports = {
css: {
sourceMap: true
},
devServer: {
proxy: {
'/api': {
target: 'http://localhost:8080',
'changeOrigin': true,
'secure': false
}
}
},
baseUrl: '',
outputDir: '../main/resources/',
assetsDir: '../main/assets/',
chainWebpack: config => {
config.module
.rule('vue')
.use('vue-loader')
.tap(options => {
return options
})
config.module
.rule('images')
.test(/\.(png|jpe?g|gif|ico)(\?.*)?$/)
.use('url-loader')
.loader('url-loader')
.options({
name: path.join('../main/assets/', 'img/[name].[ext]')
})
}
}
Everything works now, as I want it to, but the images are not copied to the correct folder.
In ".../assets/" I have the css and js folder but no img folder. In ".../ressources" next to my index.html file I have this folder.
After testing the problem on my build, I think you need two changes:
vue.config.js
module.exports = {
...
outputDir: '../main/resources/',
assetsDir: '../assets/',
...
}
and forget about the webpack plugin!
Ref config:assetsDir
assetsDir
Type: string
Default: ''
A directory (relative to outputDir) to nest generated static assets (js, css, img, fonts) under.
so assets will end up in ../main/resources/../assets/ which equates to ../main/assets/.
Image location in project
The optimum location IMO (from testing) is to use <project folder>/static which is the old CLI2 folder for static resources. In fact, any folder outside of src will do. This makes then handled as-is rather than 'webpacked'.
See Handling Static Assets
"Real" Static Assets ... In comparison, files in static/ are not processed by Webpack at all: they are directly copied to their final destination as-is, with the same filename.
Note quite true, they do get a versioning hash (see below).
This gives the following build folder structure:
../main
assets/
css/
fonts/
images/
js/
resources/
index.html
With CLI 3 the /static folder was changed to /public/static, but if you put your images there, an extra copy is made under ../main/resources/static.
If you prefer this location (to stay standard) you could remove that copy with a postbuild script in package.json, for example using npm run under Windows,
package.json
{
...
"scripts": {
"serve": "vue-cli-service serve",
"build": "vue-cli-service build",
"postbuild": "rd /s /q \"../main/resources/static/images\"",
"lint": "vue-cli-service lint",
"test:unit": "vue-cli-service test:unit"
},
"dependencies": {
Image references
In the source, I found that relative image references work fine.
For example,
import myPic from '../public/static/images/myPic.png'
gets changed to
../assets/img/myPic.ec4d96e7.png
in the built app.js.
Note the hash added for versioning.
Serving the build
I note that the folder structure you use cannot be served with a simple http-server, as index.html is in main/resources and this server cannot fetch from main/assets.
I presume your deploy mechanism takes care of that?

npm: How to set NODE_ENV in Windows (10)?

I am trying to add an npm script in package.json that sets NODE_ENV before doing something else (like running webpack). But although the syntax seems to be correct, NODE_ENV is not set when running under Windows 10.
Test script
"scripts": {
"test": "SET NODE_ENV=debug && echo %NODE_ENV%" }
The result from npm run test is "production" (provided NODE_ENV was set to "production" before running the script). Should be "debug".
What could be wrong? I even tried cross-env with no success.
Edit
To clarify my question: I cannot set any environment variable under Windows 10. And I need to call SET because I am running the script under Windows (10). Seems to be some rights problem (scripts not allowed to set environment variables?).
Another (or the actual) question would be: How can I create one script to build (using webpack) with creating minified versions of JavaScript files (for production), and one script to create non-minified versions (for development). So far I use following approach (see comments for the important parts):
Edit 2
I did not now that this probably made a difference, but in case it does: I worked with an React app created with create-react-app. I found the answer to my question, see below.
package.json:
{
"name": "test",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
// Scipts for build for development and for production
"build-dev": "SET NODE_ENV=debug webpack",
"build-release": "SET NODE_ENV=production webpack"
},
"author": "",
"license": "ISC",
"dependencies": {
"babel-core": "^6.24.1",
"babel-loader": "^7.0.0",
"babel-preset-env": "^1.4.0",
"babel-preset-react": "^6.24.1",
"debug": "^2.6.4",
"webpack": "^2.4.1"
}
}
webpack.config.js:
const path = require('path');
var webpack = require('webpack');
// Check if in debug environment
var debug = process.env.NODE_ENV !== "production";
module.exports = {
context: path.join(__dirname, 'src'),
entry: ['./index.js'],
output: {
path: path.join(__dirname, 'www/js'),
filename: 'index.js',
},
devtool: 'source-map',
module: {
rules: [
{
test: /\.jsx?$/,
exclude: /node_modules/,
use: ['babel-loader'],
}],
},
// Add the UglifyJs plugin only in debug mode
plugins: debug ? [] : [new webpack.optimize.UglifyJsPlugin({ mangle: false, sourcemap: false })],
resolve: {
modules: [
path.join(__dirname, 'node_modules')
]
}
};
This fails because setting NODE_ENV does not work for some reason. Using the command prompt directly like in the scripts:
SET NODE_ENV = debug
webpack
works by the way. That's proof that the configuration is okay, but just the npm script cannot set NODE_ENV.
Just in case you are STILL having issues setting the NODE_ENV in Windows 10 - this will help you. In your package.json file add the following:
"test": "SET \"NODE_ENV=test\""
If you plan on pushing this to Heroku - you will have to "export" the variable and your string would look like this (you are escaping the Windows-NEEDED quotes with a slash):
"test": "export NODE_ENV=test || SET \"NODE_ENV=test\""
Lastly, if you need a following command like mocha then the line would look like this:
"test": "export NODE_ENV=test || SET \"NODE_ENV=test\" && mocha server/**/*.name_of_files_plus_test.js"
Hope this helps someone :) - Mike
I found the answer to my question in the meantime, basically in the create-react-app readme: Firstly in an app created with create-react-app NODE_ENV cannot be manually overridden. Secondly, when setting environment variables, their name must start with "REACT_APP_". This was the solution for me.
In package.json:
"scripts": {
...
"build:staging": "SET REACT_APP_ENVIRONMENT=Staging && npm run build"
}
In the code:
if (process.env.REACT_APP_ENVIRONMENT === "Staging") ...
Did you try?
set DEBUG=* & npm run test
Make sure debug already installed
npm install debug --save
UPDATE:
To set environment variable in windows use
set NODE_ENV=dev //for development environment
In your case
"scripts": {
"test": "NODE_ENV=dev && echo %NODE_ENV%" }

webpack-dev-server does not watch for my file changes

When I change my files while webpack-dev-server is running, the bundle's files are not updated.
Here are my webpack.config.js and package.json files, as you can see from my npm script, I've solved running webpack watch and webpack-dev-server in the same command (npm run watch & webpack-dev-server --content-base ./ --port 9966):
webpack.config.js:
'use strict';
var ReactStylePlugin = require('react-style-webpack-plugin');
var ExtractTextPlugin = require('extract-text-webpack-plugin');
var webpack = require('webpack');
module.exports = {
devtool: 'sourcemap',
entry: ['./js/main.js'],
output: {
filename: 'bundle.js',
path: __dirname + '/assets',
publicPath: __dirname + '/'
},
module: {
loaders: [
{
test: /\.js$/,
loaders: [
ReactStylePlugin.loader(),
'jsx-loader?harmony'
]
},
{
test: /\.css$/,
loader: ExtractTextPlugin.extract('css-loader')
}
]
},
plugins: [
new ReactStylePlugin('bundle.css'),
new webpack.DefinePlugin({
'process.env': {
// To enable production mode:
//NODE_ENV: JSON.stringify('production')
}
})
]
}
package.json:
{
"name": "reactTest",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"watch": "webpack --watch",
"build": "webpack",
"web": "npm run watch & webpack-dev-server --content-base ./ --port 9966"
},
"author": "",
"license": "ISC",
"devDependencies": {
"css-loader": "^0.10.1",
"extract-text-webpack-plugin": "^0.3.8",
"jsx-loader": "^0.13.1",
"react-style-webpack-plugin": "^0.4.0",
"style-loader": "^0.10.2",
"url-loader": "^0.5.5",
"webpack": "^1.8.5",
"webpack-dev-server": "^1.8.0"
},
"dependencies": {
"react": "^0.13.1",
"react-style": "^0.5.3"
}
}
my directory structure is:
assets
bundle.css
bundle.css.map
bundle.js
bundle.js.map
js
AppActions.js
Profile.css.js
ProfileList.js
main.js
AppConstants.js
AppStore.js
Profile.js
ResultPage.js
package.json
index.html
node_modules
webpack.config.js
every file inside assets directory is generated by webpack
In order to get webpack to watch my file changes (Ubuntu 14.04), I had to increase the number of watchers (I had increased the number before, but it was still too low):
echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p
Source in the official docs: https://webpack.github.io/docs/troubleshooting.html#not-enough-watchers
I first suspected the cause to be fsevents which doesn't work on Ubuntu, but this apparently wasn't the case.
Furthermore, because now the watching and re-compiling worked, but the automatic browser refresh part didn't work, I added the --inline param to the answer of #deowk which enables the "inline mode":
webpack-dev-server --content-base ./ --port 9966 --hot --inline
Quote from the official docs: "The easiest way to use Hot Module Replacement with the webpack-dev-server is to use the inline mode."
Source: https://webpack.github.io/docs/webpack-dev-server.html#hot-module-replacement
you need to run webpack-dev-server with the --hot flag:
webpack-dev-server --content-base ./ --port 9966 --hot
Then you can access the hot-loading version localhost:9966/webpack-dev-server/
You don't need to run watch as well.
update:
This entry in your webpack config must change:
entry: ['./js/main.js'], --> entry: ['webpack/hot/dev-server' , './js/main.js']
Change your publicPath entry:
publicPath: '/assets/'
#funkybunky identified the right problem but (IMHO) fixed it the wrong way. At least in my case, webpack was trying to watch every file it used, including a deep chain of thousands of files of dependencies pulled from npm. I added this to my config, per the docs:
devServer: {
watchOptions: {
ignored: /node_modules/
}
}
Of course you legitimately could have thousands of files that might need to be watched, in which case go ahead and raise the limit, but you're probably better off ignoring vendor libraries that aren't likely to change.
I'll put this here just in case it helps anyone. My problem was the same, but caused by inconsistent capitalization of directory names and webpack alias declaration.
I had a WebGL directory which i referenced in my aliases as webgl, and unfortunately this worked for the build, but didn't work for code watching.
In my case, the error was caused by an empty space in the directory name, by changing "Repository Name" by "RepositoryName", everything worked fine !
Figured I'd post my solution as well. I had the same problem getting Flutter apps to run on OS X due to my hard drive setup.
The gist is if your project folder is in a symlinked folder, detecting the file changes may not work on OS X. Previously, we were on Webpack 3.X, I believe, and live reload/refresh worked fine in the original folder. However, after upgrading to the latest Webpack (^5.75.0) and Webpack Dev Server (^4.11.1), the hot-reloading no longer worked for me.
My original project folder was:
/Users/blakemiller/h/somefolder/v2/my-widget
The "/h" there is a symlink to: /System/Volumes/Data/projects/home/web/
I'm not sure what happened when I upgraded OS X at some point, but the upgrade changed the folders in a way that I don't really understand.
Putting the folder here instead, fixed the issue for me (no symlink):
/Users/blakemiller/my-widget
I doubt this will work for many people, as my setup is probably pretty specific, but maybe it will help someone else save 5 hours down the road...