webpack enables use of loaders to preprocess files. This allows you to bundle any static resource way beyond JavaScript. You can easily write your own loaders using Node.js.

Loaders are activated by using loadername! prefixes in require() statements, or are automatically applied via regex from your webpack configuration – see configuration.

Files

• raw-loader Loads raw content of a file (utf-8)
• val-loader Executes code as module and consider exports as JS code
• url-loader Works like the file loader, but can return a data URL if the file is smaller than a limit
• file-loader Emits the file into the output folder and returns the (relative) URL
• ref-loader Create dependencies between any files manually

JSON

• json-loader Loads a JSON file (included by default)
• json5-loader Loads and transpiles a JSON 5 file
• cson-loader Loads and transpiles a CSON file

Transpiling

• script-loader Executes a JavaScript file once in global context (like in script tag), requires are not parsed
• babel-loader Loads ES2015+ code and transpiles to ES5 using Babel
• buble-loader Loads ES2015+ code and transpiles to ES5 using Bublé
• traceur-loader Loads ES2015+ code and transpiles to ES5 using Traceur
• ts-loader or awesome-typescript-loader Loads TypeScript 2.0+ like JavaScript
• coffee-loader Loads CoffeeScript like JavaScript
• fengari-loader Loads Lua code using fengari
• elm-webpack-loader Loads Elm like JavaScript

Templating

• html-loader Exports HTML as string, require references to static resources
• pug-loader Loads Pug and Jade templates and returns a function
• markdown-loader Compiles Markdown to HTML
• react-markdown-loader Compiles Markdown to a React Component using the markdown-parse parser
• posthtml-loader Loads and transforms a HTML file using PostHTML
• handlebars-loader Compiles Handlebars to HTML
• markup-inline-loader Inline SVG/MathML files to HTML. It’s useful when applying icon font or applying CSS animation to SVG.
• twig-loader Compiles Twig templates and returns a function

Styling

• style-loader Add exports of a module as style to DOM
• css-loader Loads CSS file with resolved imports and returns CSS code
• less-loader Loads and compiles a LESS file
• sass-loader Loads and compiles a SASS/SCSS file
• postcss-loader Loads and transforms a CSS/SSS file using PostCSS
• stylus-loader Loads and compiles a Stylus file

Linting && Testing

• mocha-loader Tests with mocha (Browser/NodeJS)
• eslint-loader PreLoader for linting code using ESLint
• jshint-loader PreLoader for linting code using JSHint
• jscs-loader PreLoader for code style checking using JSCS
• coverjs-loader PreLoader to determine the testing coverage using CoverJS

Frameworks

• vue-loader Loads and compiles Vue Components
• polymer-loader Process HTML & CSS with preprocessor of choice and require() Web Components like first-class modules
• angular2-template-loader Loads and compiles Angular Components

Awesome

For more third-party loaders, see the list from awesome-webpack.