copy-webpack-plugin

What is copy-webpack-plugin?

The copy-webpack-plugin is a webpack plugin that allows you to copy files and directories from one location to another within your build process. It is commonly used to copy static assets such as images, fonts, and HTML files to the output directory defined in your webpack configuration.

What are copy-webpack-plugin's main functionalities?

Copying individual files or entire directories

This feature allows you to copy individual files or entire directories from a specified source to a destination within your output directory. The 'from' field specifies the relative or absolute path to the source file or directory, and the 'to' field specifies the relative path to the destination within the output directory.

new CopyPlugin({ patterns: [{ from: 'source', to: 'dest' }] })

Ignoring files

This feature allows you to exclude specific files or patterns from being copied. In the provided code sample, all JavaScript files are ignored and will not be copied to the destination.

new CopyPlugin({ patterns: [{ from: 'source', to: 'dest', globOptions: { ignore: ['**/*.js'] } }] })

Adding context to file paths

This feature allows you to specify a context for the file paths. The 'context' option sets a base path for the 'from' property. In the code sample, the actual path that will be copied is 'app/source'.

new CopyPlugin({ patterns: [{ from: 'source', to: 'dest', context: 'app' }] })

Transforming file content

This feature allows you to modify the content of files before they are copied. The 'transform' function receives the content of the file and its path, and it should return the new content. This can be used to minify files, add banners, or perform other transformations.

new CopyPlugin({ patterns: [{ from: 'source', to: 'dest', transform: (content, path) => { return modifyContent(content); } }] })

Other packages similar to copy-webpack-plugin

file-loader

The file-loader resolves import/require() on a file into a url and emits the file into the output directory. It is similar to copy-webpack-plugin in that it helps manage static assets, but it is more focused on handling assets within the module system.

html-webpack-plugin

The html-webpack-plugin simplifies the creation of HTML files to serve your webpack bundles. It can copy HTML files and automatically inject script tags for bundle files. It differs from copy-webpack-plugin by focusing on HTML files and their dependencies.

assets-webpack-plugin

The assets-webpack-plugin generates a JSON file with the assets produced by webpack. It is similar to copy-webpack-plugin in that it deals with the output of assets, but it does not copy files; instead, it provides a manifest of the generated assets.

README

Copy Webpack Plugin

Copies individual files or entire directories to the build directory.

Install

npm install --save-dev copy-webpack-plugin

Usage

new CopyWebpackPlugin([patterns], options)

A pattern looks like: { from: 'source', to: 'dest' }

Or, in the simple case of just a from with the default destination, you can use a string primitive instead of an object: 'source'

Pattern properties:

Name	Required	Default	Details
from	Y		examples: 'relative/file.txt' '/absolute/file.txt' 'relative/dir' '/absolute/dir' '**/*' {glob:'**/*', dot: true} Globs accept minimatch options
to	N	output root if from is file or dir resolved glob path if from is glob	examples: 'relative/file.txt' '/absolute/file.txt' 'relative/dir' '/absolute/dir' 'relative/[name].[ext]' '/absolute/[name].[ext]' Templates are file-loader patterns
toType	N	'file' if to has extension or from is file 'dir' if from is directory, to has no extension or ends in '/' 'template' if to contains a template pattern
context	N	options.context || compiler.options.context	A path that determines how to interpret the from path
flatten	N	false	Removes all directory references and only copies file names If files have the same name, the result is non-deterministic
ignore	N	[]	Additional globs to ignore for this pattern
transform	N	function(content, path) {   return content; }	Function that modifies file contents before writing to webpack
force	N	false	Overwrites files already in compilation.assets (usually added by other plugins)

Available options:

Name	Default	Details
context	compiler.options.context	A path that determines how to interpret the from path, shared for all patterns
ignore	[]	Array of globs to ignore (applied to from)
copyUnmodified	false	Copies files, regardless of modification when using watch or webpack-dev-server. All files are copied on first build, regardless of this option.
debug	'warning'	options: 'warning' - only warnings 'info' or true - file location and read info 'debug' - very detailed debugging info

Examples

var CopyWebpackPlugin = require('copy-webpack-plugin');
var path = require('path');

module.exports = {
    context: path.join(__dirname, 'app'),
    devServer: {
        // This is required for older versions of webpack-dev-server
        // if you use absolute 'to' paths. The path should be an
        // absolute path to your build destination.
        outputPath: path.join(__dirname, 'build')
    },
    plugins: [
        new CopyWebpackPlugin([
            // {output}/file.txt
            { from: 'from/file.txt' },
            
            // equivalent
            'from/file.txt',

            // {output}/to/file.txt
            { from: 'from/file.txt', to: 'to/file.txt' },
            
            // {output}/to/directory/file.txt
            { from: 'from/file.txt', to: 'to/directory' },

            // Copy directory contents to {output}/
            { from: 'from/directory' },
            
            // Copy directory contents to {output}/to/directory/
            { from: 'from/directory', to: 'to/directory' },
            
            // Copy glob results to /absolute/path/
            { from: 'from/directory/**/*', to: '/absolute/path' },

            // Copy glob results (with dot files) to /absolute/path/
            {
                from: {
                    glob:'from/directory/**/*',
                    dot: true
                },
                to: '/absolute/path'
            },

            // Copy glob results, relative to context
            {
                context: 'from/directory',
                from: '**/*',
                to: '/absolute/path'
            },
            
            // {output}/file/without/extension
            {
                from: 'path/to/file.txt',
                to: 'file/without/extension',
                toType: 'file'
            },
            
            // {output}/directory/with/extension.ext/file.txt
            {
                from: 'path/to/file.txt',
                to: 'directory/with/extension.ext',
                toType: 'dir'
            }
        ], {
            ignore: [
                // Doesn't copy any files with a txt extension    
                '*.txt',
                
                // Doesn't copy any file, even if they start with a dot
                '**/*',

                // Doesn't copy any file, except if they start with a dot
                { glob: '**/*', dot: false }
            ],

            // By default, we only copy modified files during
            // a watch or webpack-dev-server build. Setting this
            // to `true` copies all files.
            copyUnmodified: true
        })
    ]
};

FAQ

"EMFILE: too many open files" or "ENFILE: file table overflow"

Globally patch fs with graceful-fs

npm install graceful-fs --save-dev

At the top of your webpack config, insert this

var fs = require('fs');
var gracefulFs = require('graceful-fs');
gracefulFs.gracefulify(fs);

See this issue for more details

This doesn't copy my files with webpack-dev-server

Starting in version 3.0.0, we stopped using fs to copy files to the filesystem and started depending on webpack's in-memory filesystem:

... webpack-dev-server will serve the static files in your build folder. It’ll watch your source files for changes and when changes are made the bundle will be recompiled. This modified bundle is served from memory at the relative path specified in publicPath (see API). It will not be written to your configured output directory.

If you must have webpack-dev-server write to your output directory, you can force it with the write-file-webpack-plugin.

Maintainers

Juho Vepsäläinen

Joshua Wiens

Michael Ciniawsky

Alexander Krasnoyarov