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Webpack breaking change

I am trying to build a react app but each time I run npm start, I am greeted with this message
Module not found: Error: Can't resolve 'buffer' in '/Users/abdus/Documents/GitHub/keywords-tracker/node_modules/buffer-equal-constant-time'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.
It gives the same message for a few different modules. I have tried npm installing these modules but the error persists

this is my webpack set up that works. you should install all the packages that listed in fallback:
// const path = require("path");
const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const CopyWebpackPlugin = require("copy-webpack-plugin");
const webpack = require("webpack");
module.exports = {
mode: "development",
target: "web",
entry: ["regenerator-runtime/runtime", "./src/index.js"],
output: {
filename: "bundle.js",
path: path.join(__dirname, "dist"),
publicPath: "/",
},
resolve: {
extensions: [".js", ".css"],
alias: {
// add as many aliases as you like!
components: path.resolve(__dirname, "src/components"),
},
fallback: {
// path: require.resolve("path-browserify"),
fs: false,
assert: require.resolve("assert/"),
os: require.resolve("os-browserify/browser"),
constants: require.resolve("constants-browserify"),
stream: require.resolve("stream-browserify"),
crypto: require.resolve("crypto-browserify"),
http: require.resolve("stream-http"),
https: require.resolve("https-browserify"),
},
},
// devtool: "eval-cheap-source-map",
devtool: "eval",
module: {
rules: [
{ test: /\.(js|jsx)/, loader: "babel-loader", exclude: /node_modules/ },
{ test: /\.css$/, use: ["style-loader", "css-loader"] },
// {
// test: /\.m?js/,
// resolve: {
// fullySpecified: false
// }
// },
{
test: /\.(woff(2)?|ttf|eot|jpg|jpeg|png|gif)(\?v=\d+\.\d+\.\d+)?$/,
use: [
{
loader: "file-loader",
options: {
name: "[name].[contenthash].[ext]",
outputPath: "fonts/",
},
},
],
},
{
test: /\.svg$/,
use: [
{
loader: "svg-url-loader",
options: {
limit: 10000,
},
},
],
},
{
test: /\.json5$/i,
loader: "json5-loader",
type: "javascript/auto",
options: {
esModule: true,
},
},
],
},
devServer: {
contentBase: path.join(__dirname, "build"),
historyApiFallback: true,
overlay: true,
},
plugins: [
new HtmlWebpackPlugin({
title: "NFT",
template: "src/index.html",
}),
// new CopyWebpackPlugin({
// patterns: [{ from: "assets", to: "assets" }],
// }),
],
};
you can get this webpack5-Boilerplate
Since there are too many polyfills, instead of manually installing all, you can use node-polyfill-webpack-plugin package. instead of fallback property
const NodePolyfillPlugin = require("node-polyfill-webpack-plugin");
plugins: [
new HtmlWebpackPlugin({
title: "esBUild",
template: "src/index.html",
}),
// instead of fallback
new NodePolyfillPlugin(),
// new webpack.ProvidePlugin({
// process: "process/browser",
// Buffer: ["buffer", "Buffer"],
// React: "react",
}),
],

It seems like you are using a front-end react app and some dependency is internally using the buffer module which is only available in target: node under webpack. So you will need to add a polyfill for the same.
module.exports = {
resolve: {
fallback: {
buffer: require.resolve('buffer'),
}
},
}
You can check the docs here at webpack: https://webpack.js.org/configuration/resolve/#resolvefallback
From Webpack 5 onwards, webpack doesn't polyfill for browser-based applications.

How to solve ChunkLoadError: Loading hot update chunk second_app failed in webpack 5?

while setup a new project for development, the app is not hot reloading. The app consists of multiple apps separated in its different folders.Currently, there are 2 apps html_nodes_prototype and second_app in src/apps folder. Each app consist of index.html, style.css and main.js when I visit the link http://localhost:8080/second_app/second_app.html, the app shows but If I change something in src/apps/second_app/main.js. It doesn't hot reload, I've to manually reload to get changes. I've set up a webpack-dev-server. Error prompts in the console. I couldn't figure out what's wrong with the config file.
Error in console
[HMR] Update failed: ChunkLoadError: Loading hot update chunk second_app failed.
(missing: http://localhost:8080/second_app.5b0047c2bf2b48c8a084.hot-update.js)
at http://localhost:8080/second_app/second_app.bundle.js:987:26
at new Promise (<anonymous>)
at loadUpdateChunk (http://localhost:8080/second_app/second_app.bundle.js:982:20)
at http://localhost:8080/second_app/second_app.bundle.js:1411:29
at Array.forEach (<anonymous>)
at Object.__webpack_require__.hmrC.jsonp (http://localhost:8080/second_app/second_app.bundle.js:1406:22)
at http://localhost:8080/second_app/second_app.bundle.js:819:45
at Array.reduce (<anonymous>)
at http://localhost:8080/second_app/second_app.bundle.js:815:53
paths.js
const path = require("path");
module.exports = {
// Source files
src: path.resolve(__dirname, "../src"),
// Production build files
build: path.resolve(__dirname, "../dist"),
// public path
public: path.resolve(__dirname, "../public/"),
};
webpack.dev.js
const common = require("./webpack.common");
var HtmlWebpackPlugin = require("html-webpack-plugin");
const merge = require("webpack-merge").merge;
const paths = require("./paths");
module.exports = merge(common, {
mode: "development",
output: {
filename: "[name]/[name].bundle.js",
path: paths.build,
},
module: {
rules: [
{ test: /\.scss$/, use: ["style-loader", "css-loader", "sass-loader"] },
{ test: /\.css$/, use: ["style-loader", "css-loader"] },
],
},
devServer: {
historyApiFallback: true,
// contentBase: paths.build,
open: true,
compress: true,
hot: true,
port: 8080,
},
plugins: [
new HtmlWebpackPlugin({
filename: "html_nodes_prototype/html_nodes_prototype.html",
title: "HTML Nodes",
template: "src/apps/html_nodes_prototype/index.html",
chunks: ["html_nodes_prototype", "vendor"],
}),
new HtmlWebpackPlugin({
filename: "second_app/second_app.html",
title: "Second app",
hot: true,
template: "src/apps/second_app/index.html",
chunks: ["second_app", "vendor"],
}),
],
});
webpack.common.js
const paths = require("./paths");
module.exports = {
mode: "development",
entry: {
html_nodes_prototype: paths.src + "/apps/html_nodes_prototype/main.js",
second_app: paths.src + "/apps/second_app/main.js",
vendor: paths.src + "/apps/_vendor/vendor.js",
},
module: {
rules: [{ test: /\.m?js$/, use: ["babel-loader"] }],
},
};

Adding runtimeChunk: 'single' to webpack.dev.js works for me. Found the answer here
module.exports = {
...,
optimization: {
runtimeChunk: 'single'
},
...
}

How do I disable webpack 4 code splitting?

I'm using webpack 4.43.0.
How do I prevent codesplitting from happening in webpack? All these files are created - 0.bundle.js up to 11.bundle.js (alongside the expected bundle.js), when I run webpack. Here's my webpack config:
/* eslint-env node */
const path = require('path');
module.exports = {
entry: './media/js/src/main.jsx',
mode: process.env.WEBPACK_SERVE ? 'development' : 'production',
output: {
path: path.resolve(__dirname, 'media/js'),
filename: 'bundle.js'
},
resolve: {
extensions: ['*', '.js', '.jsx']
},
module: {
rules: [
{
test: /\.(js|jsx)$/,
include: path.resolve(__dirname, 'media/js/src'),
exclude: /node_modules/,
use: {
loader: 'babel-loader',
options: {
presets: ['#babel/preset-env', '#babel/preset-react']
}
}
}
]
}
};

You can use webpack's LimitChunkCountPlugin to limit the chunk count produced by code splitting:
In your webpack.config.js file:
const webpack = require('webpack');
module.exports = {
plugins: [
new webpack.optimize.LimitChunkCountPlugin({
maxChunks: 1
})
],
...
};
You could also pass the --optimize-max-chunks option to the webpack command directly.
So, in your package.json file:
{
"scripts": {
"build": "webpack --optimize-max-chunks 1",
...
},
...
}
Now, when you run npm run build, webpack will build only one file (or "chunk").

// Full list of options: https://quasar.dev/quasar-cli/quasar-conf-js#Property%3A-build
build: {
scopeHoisting: true,
vueRouterMode: 'history', // available values: 'hash', 'history'
showProgress: true,
gzip: false,
analyze: false,
distDir: 'dist',
productName:'pos_host_ui',
minify:true,
// Options below are automatically set depending on the env, set them if you want to override
// extractCSS: false,
// https://quasar.dev/quasar-cli/cli-documentation/handling-webpack
extendWebpack (cfg) {
const webpack = require('webpack');
cfg.plugins.push(
new webpack.optimize.LimitChunkCountPlugin({
maxChunks: 1
})
);
cfg.module.rules.push({
resourceQuery: /blockType=i18n/,
type: 'javascript/auto',
use: [
{ loader: '#kazupon/vue-i18n-loader' },
{ loader: 'yaml-loader' },
]
});
}

How to bundle and copy CSS files from source folder to dist folder?

Here is my folder structure:
I want to minify and bundle the CSS files inside my src/css folder and output it as a single CSS file inside dist. All the examples I've seen so far recommend require-ing the CSS file inside a JS file. I do not want that. Is there a way to configure in webpack.config.js to just minify and copy these files?

Got it working.
Install dev-dependecies
npm i extract-text-webpack-plugin --save-dev
npm i css-loader --save-dev
webpack.config.js
const webpack = require('webpack');
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const extractCSS = new ExtractTextPlugin('bundle.min.css')
module.exports = {
entry: {
'bundle.min.css': [
__dirname + '/src/styles/abc.css',
__dirname + '/src/styles/xyz.css',
__dirname + '/src/styles/mno.css'
]
},
devtool: '',
output: {
path: __dirname + '/dist/styles/',
filename: '[name]'
},
module: {
rules: [{
test: /\.css$/i,
use: extractCSS.extract({
use: {
loader: 'css-loader',
options: {
minimize: true
}
}
})
}]
},
resolve: {
alias: {},
modules: [],
extensions: ['.css']
},
plugins: [
extractCSS
]
};
bundle.min.css will get generated. Based on minimize: true/false, minification will be decided. Enjoy!

It will go in three steps;
first you will need two loaders and plugin; named css-loader and style-loader and extract-text-webpack-plugin respectively.
Then your config might look like following:
const webpack = require('webpack');
const ExtractTextPlugin = require("extract-text-webpack-plugin");
const path = require('path');
module.exports = {
entry: {
app: './src/index.js'
},
output: {
path: 'dist',
filename: 'js/[name]-bundle.js'
},
devtool: "cheap-source-map",
resolveLoader: {
modules: [
'node_modules',
path.join(__dirname, '../node_modules'),
]
},
module: {
loaders: [
{
test: /.css?$/,
loader: ExtractTextPlugin.extract({ fallback: 'style-loader', use: 'css-loader' }),
exclude: /node_modules/
}
]
},
plugins: [
new ExtractTextPlugin("css/[name].css"),
new webpack.optimize.UglifyJsPlugin({
compress: {
warnings: false,
screw_ie8: true,
conditionals: true,
unused: true,
comparisons: true,
sequences: true,
dead_code: true,
evaluate: true,
join_vars: true,
if_return: true
},
output: {
comments: false
}
}),
]
}
And then in your entry file, require them like require('./style.css');
Remember, it will follow the paths as your source.
If you are loading font files and images in you css, you might need the file-loader plugin as well which will copy all assets in directory.
The file-loader config will look like:
{
test: /.png?$/,
loader: 'file-loader?name=img/[name].[ext]',
exclude: /node_modules/
}
The UgligyJsPlugin will also minify the CSS.

How to minimize javascript with Webpack?

I'm trying to minimize my bundle.js file with webpack, but getting errors in my config:
module.exports = {
entry: "./entry.js",
output: {
devtoolLineToLine: true,
sourceMapFilename: "./bundle.js.map",
pathinfo: true,
path: __dirname,
filename: "bundle.js"
},
module: {
loaders: [
{ test: /\.css$/, loader: "style!css" }
]
},
plugins: [
new webpack.optimize.UglifyJsPlugin({
include: /\.min\.js$/,
minimize: true
})
]
};
The error:
/Users/leongaban/Projects/TickerTags/ionic/TickerTags/www/webpack.config.js:16
new webpack.optimize.UglifyJsPlugin({
^
ReferenceError: webpack is not defined

Seems like you're missing var webpack = require('webpack'); at the top of your configuration file.
It works for me this way