Develop Reference

Public file is missing from build/public in Webpack [duplicate]

I'm trying to move from Gulp to Webpack. In Gulp I have task which copies all files and folders from /static/ folder to /build/ folder. How to do the same with Webpack? Do I need some plugin?

Requiring assets using the file-loader module is the way webpack is intended to be used (source). However, if you need greater flexibility or want a cleaner interface, you can also copy static files directly using my copy-webpack-plugin (npm, Github). For your static to build example:
const CopyWebpackPlugin = require('copy-webpack-plugin');
module.exports = {
context: path.join(__dirname, 'your-app'),
plugins: [
new CopyWebpackPlugin({
patterns: [
{ from: 'static' }
]
})
]
};
Compatibility note: If you're using an old version of webpack like webpack#4.x.x, use copy-webpack-plugin#6.x.x. Otherwise use latest.

You don't need to copy things around, webpack works different than gulp. Webpack is a module bundler and everything you reference in your files will be included. You just need to specify a loader for that.
So if you write:
var myImage = require("./static/myImage.jpg");
Webpack will first try to parse the referenced file as JavaScript (because that's the default). Of course, that will fail. That's why you need to specify a loader for that file type. The file- or url-loader for instance take the referenced file, put it into webpack's output folder (which should be build in your case) and return the hashed url for that file.
var myImage = require("./static/myImage.jpg");
console.log(myImage); // '/build/12as7f9asfasgasg.jpg'
Usually loaders are applied via the webpack config:
// webpack.config.js
module.exports = {
...
module: {
loaders: [
{ test: /\.(jpe?g|gif|png|svg|woff|ttf|wav|mp3)$/, loader: "file" }
]
}
};
Of course you need to install the file-loader first to make this work.

If you want to copy your static files you can use the file-loader in this way :
for html files :
in webpack.config.js :
module.exports = {
...
module: {
loaders: [
{ test: /\.(html)$/,
loader: "file?name=[path][name].[ext]&context=./app/static"
}
]
}
};
in your js file :
require.context("./static/", true, /^\.\/.*\.html/);
./static/ is relative to where your js file is.
You can do the same with images or whatever.
The context is a powerful method to explore !!

One advantage that the aforementioned copy-webpack-plugin brings that hasn't been explained before is that all the other methods mentioned here still bundle the resources into your bundle files (and require you to "require" or "import" them somewhere). If I just want to move some images around or some template partials, I don't want to clutter up my javascript bundle file with useless references to them, I just want the files emitted in the right place. I haven't found any other way to do this in webpack. Admittedly it's not what webpack originally was designed for, but it's definitely a current use case.
(#BreakDS I hope this answers your question - it's only a benefit if you want it)

Webpack 5 adds Asset Modules which are essentially replacements for common file loaders. I've copied a relevant portion of the documentation below:
asset/resource emits a separate file and exports the URL. Previously achievable by using file-loader.
asset/inline exports a data URI of the asset. Previously achievable by using url-loader.
asset/source exports the source code of the asset. Previously achievable by using raw-loader.
asset automatically chooses between exporting a data URI and emitting a separate file. Previously achievable by using url-loader with asset size limit.
To add one in you can make your config look like so:
// webpack.config.js
module.exports = {
...
module: {
rules: [
{
test: /\.(jpe?g|gif|png|svg|woff|ttf|wav|mp3)$/,
type: "asset/resource"
}
]
}
};
To control how the files get output, you can use templated paths.
In the config you can set the global template here:
// webpack.config.js
module.exports = {
...
output: {
...
assetModuleFilename: '[path][name].[hash][ext][query]'
}
}
To override for a specific set of assets, you can do this:
// webpack.config.js
module.exports = {
...
module: {
rules: [
{
test: /\.(jpe?g|gif|png|svg|woff|ttf|wav|mp3)$/,
type: "asset/resource"
generator: {
filename: '[path][name].[hash][ext][query]'
}
}
]
}
};
The provided templating will result in filenames that look like build/images/img.151cfcfa1bd74779aadb.png. The hash can be useful for cache busting etc. You should modify to your needs.

Above suggestions are good. But to try to answer your question directly I'd suggest using cpy-cli in a script defined in your package.json.
This example expects node to somewhere on your path. Install cpy-cli as a development dependency:
npm install --save-dev cpy-cli
Then create a couple of nodejs files. One to do the copy and the other to display a checkmark and message.
copy.js
#!/usr/bin/env node
var shelljs = require('shelljs');
var addCheckMark = require('./helpers/checkmark');
var path = require('path');
var cpy = path.join(__dirname, '../node_modules/cpy-cli/cli.js');
shelljs.exec(cpy + ' /static/* /build/', addCheckMark.bind(null, callback));
function callback() {
process.stdout.write(' Copied /static/* to the /build/ directory\n\n');
}
checkmark.js
var chalk = require('chalk');
/**
* Adds mark check symbol
*/
function addCheckMark(callback) {
process.stdout.write(chalk.green(' ✓'));
callback();
}
module.exports = addCheckMark;
Add the script in package.json. Assuming scripts are in <project-root>/scripts/
...
"scripts": {
"copy": "node scripts/copy.js",
...
To run the sript:
npm run copy

The way I load static images and fonts:
module: {
rules: [
....
{
test: /\.(jpe?g|png|gif|svg)$/i,
/* Exclude fonts while working with images, e.g. .svg can be both image or font. */
exclude: path.resolve(__dirname, '../src/assets/fonts'),
use: [{
loader: 'file-loader',
options: {
name: '[name].[ext]',
outputPath: 'images/'
}
}]
},
{
test: /\.(woff(2)?|ttf|eot|svg|otf)(\?v=\d+\.\d+\.\d+)?$/,
/* Exclude images while working with fonts, e.g. .svg can be both image or font. */
exclude: path.resolve(__dirname, '../src/assets/images'),
use: [{
loader: 'file-loader',
options: {
name: '[name].[ext]',
outputPath: 'fonts/'
},
}
]
}
Don't forget to install file-loader to have that working.

You can write bash in your package.json:
# package.json
{
"name": ...,
"version": ...,
"scripts": {
"build": "NODE_ENV=production npm run webpack && cp -v <this> <that> && echo ok",
...
}
}

Most likely you should use CopyWebpackPlugin which was mentioned in kevlened answer. Alternativly for some kind of files like .html or .json you can also use raw-loader or json-loader. Install it via npm install -D raw-loader and then what you only need to do is to add another loader to our webpack.config.js file.
Like:
{
test: /\.html/,
loader: 'raw'
}
Note: Restart the webpack-dev-server for any config changes to take effect.
And now you can require html files using relative paths, this makes it much easier to move folders around.
template: require('./nav.html')

I was stuck here too. copy-webpack-plugin worked for me.
However, 'copy-webpack-plugin' was not necessary in my case (i learned later).
webpack ignores root paths
example
<img src="/images/logo.png'>
Hence, to make this work without using 'copy-webpack-plugin'
use '~' in paths
<img src="~images/logo.png'>
'~' tells webpack to consider 'images' as a module
note:
you might have to add the parent directory of images directory in
resolve: {
modules: [
'parent-directory of images',
'node_modules'
]
}
Visit https://vuejs-templates.github.io/webpack/static.html

The webpack config file (in webpack 2) allows you to export a promise chain, so long as the last step returns a webpack config object. See promise configuration docs. From there:
webpack now supports returning a Promise from the configuration file. This allows to do async processing in you configuration file.
You could create a simple recursive copy function that copies your file, and only after that triggers webpack. E.g.:
module.exports = function(){
return copyTheFiles( inpath, outpath).then( result => {
return { entry: "..." } // Etc etc
} )
}

lets say all your static assets are in a folder "static" at the root level and you want copy them to the build folder maintaining the structure of subfolder, then
in your entry file) just put
//index.js or index.jsx
require.context("!!file?name=[path][name].[ext]&context=./static!../static/", true, /^\.\/.*\.*/);

In my case I used webpack for a wordpress plugin to compress js files, where the plugin files are already compressed and need to skip from the process.
optimization: {
minimize: false,
},
externals: {
"jquery": "jQuery",
},
entry: glob.sync('./js/plugin/**.js').reduce(function (obj, el) {
obj[path.parse(el).name] = el;
return obj
}, {}),
output: {
path: path.resolve(__dirname, './js/dist/plugin'),
filename: "[name].js",
clean: true,
},
That used to copy the js file as it is to the build folder. Using any other methods like file-loader and copy-webpack create issues with that.
Hope it will help someone.

Can you compile a TS file with webpack separately from Vue application?

So I have a Vue 3 + Typescript app. npm run build of course takes the app and compiles it into the dist folder so it can be deployed. I have a web worker typescript file that I would like to be compiled separately so that it ends up in the root of the dist folder with the name worker.js. Here is what I'm looking for:
dist
|- worker.js
src
|- worker.ts // This gets compiled to js file in dist folder
I tried doing this by using webpack's DefinePlugin in my vue.config.js like so:
const webpack = require('webpack')
module.exports = {
configureWebpack: {
plugins: [
new webpack.DefinePlugin({
entry: `${__dirname}/src/worker.ts`,
module: {
rules: [
{
test: /worker\.ts$/,
use: 'ts-loader',
exclude: /node-modules/
}
]
},
resolve: {
extensions: ['.ts']
},
output: {
filename: 'worker.js',
path: `${__dirname}/dist`
}
})
],
resolve: {
alias: {
vue$: 'vue/dist/vue.esm-bundler.js'
}
}
}
}
Unfortunately this doesn't work, npm run build just completely ignores the worker.ts file and it doesn't show up in the dist folder anywhere, not even as a chunk. Any suggestions? Or is what I'm wanting to do even possible? Thanks for any help!

I was able to get the desired result using esbuild. Now I can write my web worker in Typescript and use classes and functions from my Vue app. It also compiles lightning fast. I just added the node ./esbuild.js command to my npm run dev and npm run build scripts, and now it compiles to the public folder before the Vue app builds. Here is my esbuild.js file.
const esbuild = require('esbuild')
const { nodeExternalsPlugin } = require('esbuild-node-externals')
const config = {
entryPoints: ['./src/worker.ts'],
outfile: 'public/worker.js',
bundle: true,
minify: false,
logLevel: 'silent',
plugins: [nodeExternalsPlugin()]
}
esbuild.build(config).catch(() => process.exit(1))
Let me know if you have any questions, I'd be happy to help anyone out getting this working.

bundle web workers as integral part of npm package with single file webpack output

I am writing an npm package which is a plugin for the popular library leafletjs. I am using webpack to bundle the package. I want this package to be able to spawn and destroy some web workers on command. The web worker code is part of my source files. But I want to be able to distribute my package both as an npm module, or through a cdn, meaning it must be compiled down to a singular file that can be included through an HTML header. I am using webpack to do it. So lets say I have a worker file:
// sample.worker.js
import { doSomeStuff } from './algorithm.js';
onmessage = function (e) {
const results = doSomeStuff(e.data)
postMessage({
id: e.data.id,
message: results',
});
};
Fairly simple, but an important point here is that my worker is actually importing some code from an algorithm file, which is in turn importing some node modules. My worker is used in the main module somewhere, like this:
// plugin.js
import SampleWorker from 'worker-loader!./workers/dem.worker.js';
export function plugin(){
// do some stuff
const worker = new SampleWorker()
worker.postMessage(someData);
worker.onmessage = (event) => {};
}
My webpack config looks like this:
module.exports = {
entry: './src/index',
output: {
path: path.resolve(__dirname, 'build'),
filename: 'my-plugin.js',
},
resolve: {
extensions: ['.ts', '.tsx', '.js', '.json'],
},
module: {
rules: [
{
test: /\.worker\.js$/,
loader: 'worker-loader',
options: {
inline: 'fallback',
},
},
{
test: /\.(ts|js)x?$/,
exclude: /node_modules/,
loader: 'babel-loader',
},
],
},
externals: { ... },
plugins: { ... }
};
This doesn't work as is - webpack tries to bundle the main bundle and each worker script file under the same name. Changing to filename: '[name].js' under output fixes this issue, but gives me many files - one for the main bundle, and another file for each worker file in my source code.
Reading the webpack options, I thought that using the inline: 'fallback' option would actually create a Blob for each worker and bundle that into the main output file. That is not happening.
So far my solution is to write my workers as blobs, like this:
// workers.js
const workerblob = new Blob([`
// cannot import in a blob!
// have to put algorithm.js code here, copy in any external module code here
onmessage = function (e) {
const results = doSomeStuff(e.data)
postMessage({
id: e.data.id,
message: results,
});
};
`])
export const sampleWorker = URL.createObjectURL(workerblob);
// my-plugin.js
import { sampleWorker } from 'workers.js'
const worker = new Worker(sampleWorker)
This does in fact work - webpack now outputs 1 single file which includes the worker code. Using a modified version of this from this answer, I can at least place my code inside a function( ...code... ){}.toString() format, so I can at least get intellisense, syntax highlighting, etc. But I cannot use imports.
How can I use webpack to bundle my workers so that the entire bundle ends up in 1 file, worker code and all?

Pass an argument to Webpack from Node.js

I'm trying to build both minified and unminified versions of my app (js and css) using Webpack.
This can be easily done via command-line interface using -p or --optimize-minimize switch:
webpack
webpack -p
However, I would like to perform these actions with just one command, so I decided to write a small Node.js script which would run both of these Webpack builds:
var webpack = require('webpack');
var config = require('./webpack.config');
webpack(config, callback); // Build unminified version
So the question is: can I pass the aforementioned -p argument to Webpack from the Node.js script in order to build the minified version? Or maybe there is a simpler way of solving my particular problem?
Of course, I can use child_process.exec(), but I don't think it's an authentic Node.js way.

Create your default config to webpack an unminified version. Run webpack with that config. Change the configuration from code and run webpack again. Here is a code example.
var webpack = require('webpack');
//assuming the config looks like this.
var config = {
entry: "./entry.js",
output: {
devtoolLineToLine: true,
sourceMapFilename: "./bundle.js.map",
pathinfo: true,
path: __dirname,
filename: "bundle.js"
},
module: {
loaders: [
{ test: /\.css$/, loader: "style!css" }
]
},
plugins: []
};
webpack(config).run(); // Build unminified version
config.output.filename = 'bundle.min.js'
config.plugins = [
new webpack.optimize.UglifyJsPlugin({
include: /\.min\.js$/,
minimize: true
})];
webpack(config).run(); // Build minified version

Key p is an alias to setting node environment variable process.env.NODE_ENV="production" as described here

Webpack exclude entries for CommonsChunkPlugin

I am trying to set up webpack production configuration. All looks well. However, I realized that while using the commons chunk plugin, it covers all the files in common as expected. What I want to do is, separation of common library modules and common application modules. My config file is :
module.exports = {
entry: {
lib: ["react", "react-dom"],
app: "./ui-v2/app/app.js",
app2: "./ui-v2/app/app2.js"
},
output: {
path: path.join(__dirname, "target/ui/v2"),
filename: "/app/[name].[chunkhash].min.js"
},
module: {
loaders: [
{
test: /\.js$/,
exclude: /node_modules/,
loader: "babel-loader"
},
{
test: /\.(png|jpg|svg)/,
loader: "file-loader?name=img/[name].[hash].[ext]"
// loaders: ["url", "image-webpack"]
},
{
test: /\.scss$/,
loader: ExtractTextPlugin.extract("style-loader", "css-loader!autoprefixer-loader!sass-loader", {
publicPath: __dirname
})
},
{
test: /\.(woff|woff2|ttf|eot)$/,
loader: "file-loader?name=fonts/[name].[hash].[ext]"
}
]
},
plugins: [
clean,
new webpack.optimize.CommonsChunkPlugin("common", "app/common.[chunkhash].js"),
new webpack.ProvidePlugin({
React: "react",
ReactDOM: "react-dom",
$: "jquery",
_: "lodash"
}),
new webpack.optimize.UglifyJsPlugin({
compress: {
warnings: false
sourceMap: true
},
mangle: {
except: ["exports", "import", "$", "_", "require", "React", "ReactDOM"]
}
}),
new ExtractTextPlugin("styles/[name].[contenthash].css"),
new Manifest()
]
}
Basically I have 3 modules in the app; app.js, app2.js and a common component user.js.
What I want to achieve is to bundle all library related files like react, react-dom, lodash, etc in a lib bundle, and common application components like user.js in a common bundle. In order to do this, I thought there might be an option to exclude the files that I don't want them to go to "common" file. If I use this output, what is the point for long term caching files for library bundles because whenever I get a common component in my project, they will go into the common bundle and the content hash will be different, but nothing changes in this library files like react, jquery, lodash, etc.
Anyway, what I have at the end of build process is everything still goes into the common bundle and lib has nothing and the file sizes are :
app.<hash>.min.js -> 3.05KB
app2.<hash>.min.js -> 3.05KB
lib.<hash>.min.js -> 165 Bytes (has almost nothing!)
common.<hash>.js -> 678 KB
Is there any way to achieve what I want or what would be the best approach to a production build in similar cases? Thank you!

Its because the first parameter for CommonsChunkPlugin is "common" where it should be "lib". The plugin picks up the entry with a name matching with the value of its first parameter.
A simple example config picked from webpack's wiki -
var webpack = require("webpack");
module.exports = {
entry: {
app: "./app.js",
vendor: ["jquery", "underscore", ...],
},
output: {
filename: "bundle.js"
},
plugins: [
new webpack.optimize.CommonsChunkPlugin(/* chunkName= */"vendor", /* filename= */"vendor.bundle.js")
]
};
Note that the "vendor" entry is again specified in CommonsChunkPlugin

You should check out Webpack's DLL Plugin.
https://github.com/webpack/webpack/blob/cb3d8e2097503c7245c5dda5b7a6e9d63421a72b/examples/dll/README.md
With this plugin you bundle up common 3rd party vendor dependencies such as React and friends in a DLL, which is essentially just a JSON Manifest that goes along with your requires wrapped in webpack context and cached to disk.
In your project code, you would have your shared components which depend on React and friends, and you would have your application code which depend on your shared components as well as react and friends.
Your project would incorporate the DLL Reference plugin as you can see here:
https://github.com/webpack/webpack/blob/cb3d8e2097503c7245c5dda5b7a6e9d63421a72b/examples/dll-user/README.md
This will see to it that your shared components and your application code pull React and other 3rd party modules from the same DLL bundle. This can help improve build times and the performance of the dev server and hot module reloading.