file-loader

What is file-loader?

The file-loader npm package is used to process files such as images, fonts, and other binary assets within a webpack build process. It can copy files to the output directory and resolve import/require() on a file into a url.

What are file-loader's main functionalities?

Importing Images

Allows importing image files directly in JavaScript or TypeScript files. The file-loader processes the import and replaces it with the final path to the output file.

import img from './file.png';

Configuring Output Path and Filenames

Configures webpack to output files with a specific naming pattern and to a specific directory. It also allows setting a public path for the files when they are referenced in the browser.

module.exports = {
  module: {
    rules: [
      {
        test: /\.(png|jpe?g|gif)$/i,
        use: [
          {
            loader: 'file-loader',
            options: {
              name: '[path][name].[ext]',
              outputPath: 'images/',
              publicPath: 'assets/',
            },
          },
        ],
      },
    ],
  },
};

Handling Fonts

Enables the inclusion and processing of font files in various formats. The file-loader will handle these assets and output them to a specified directory.

module.exports = {
  module: {
    rules: [
      {
        test: /\.(woff|woff2|eot|ttf|otf)$/i,
        use: [
          {
            loader: 'file-loader',
            options: {
              name: '[name].[ext]',
              outputPath: 'fonts/',
            },
          },
        ],
      },
    ],
  },
};

Other packages similar to file-loader

url-loader

The url-loader works like the file-loader, but can return a Data URL if the file is smaller than a byte limit. This can reduce the number of HTTP requests for small files.

raw-loader

The raw-loader allows importing files as a string. This is useful for importing things like HTML or SVG directly into your JavaScript code, which is different from file-loader's typical binary asset handling.

copy-webpack-plugin

This plugin allows copying individual files or entire directories to the build directory. It is more flexible than file-loader for simply copying files without processing them through webpack's module system.

README

file loader for webpack

Usage

Documentation: Using loaders

var url = require("file!./file.png");
// => emits file.png as file in the output directory and returns the public url
// => returns i. e. "/public-path/0dcbbaa701328a3c262cfd45869e351f.png"

By default the filename of the resulting file is the MD5 hash of the file's contents with the original extension of the required resource.

Filename templates

You can configure a custom filename template for your file using the query parameter name. For instance, to copy a file from your context directory into the output directory retaining the full directory structure, you might use ?name=[path][name].[ext].

Filename template placeholders

• [ext] the extension of the resource
• [name] the basename of the resource
• [path] the path of the resource relative to the context query parameter or option.
• [hash] the hash or the content
• [<hashType>:hash:<digestType>:<length>] optionally you can configure
  • other hashTypes, i. e. sha1, md5, sha256, sha512
  • other digestTypes, i. e. hex, base26, base32, base36, base49, base52, base58, base62, base64
  • and length the length in chars
• [N] the N-th match obtained from matching the current file name against the query param regExp

Examples

require("file?name=js/[hash].script.[ext]!./javascript.js");
// => js/0dcbbaa701328a3c262cfd45869e351f.script.js

require("file?name=html-[hash:6].html!./page.html");
// => html-109fa8.html

require("file?name=[hash]!./flash.txt");
// => c31e9820c001c9c4a86bce33ce43b679

require("file?name=[sha512:hash:base64:7].[ext]!./image.png");
// => gdyb21L.png
// use sha512 hash instead of md5 and with only 7 chars of base64

require("file?name=img-[sha512:hash:base64:7].[ext]!./image.jpg");
// => img-VqzT5ZC.jpg
// use custom name, sha512 hash instead of md5 and with only 7 chars of base64

require("file?name=picture.png!./myself.png");
// => picture.png

require("file?name=[path][name].[ext]?[hash]!./dir/file.png")
// => dir/file.png?e43b20c069c4a01867c31e98cbce33c9

License

MIT (http://www.opensource.org/licenses/mit-license.php)