---

$3

We rely on your help to keep this project up to date and work with the latest versions of craco and react-scripts.

Before you send a PR, please check the following:

- 100% test coverage

``
yarn test
`

- Code is formatted with Prettier

`
yarn format
`

- No ESLint warnings

`
yarn lint
`

- No security vulnerabilities in any NPM packages

`
yarn audit
`

You are also welcome to add your GitHub username to the Contributors section at the bottom of this README. (_optional_)

$3

Pull requests will be ignored and closed if there is a failing build on Travis CI.

---

Craco Less Plugin

This is a craco plugin that adds Less support to create-react-app version >= 2.

> Use react-app-rewired for create-react-app version 1.

Ant Design

If you want to use Ant Design with create-react-app,
you should use the craco-antd plugin.
craco-antd includes Less and babel-plugin-import (to only include the required CSS.) It also makes it easy to customize the theme variables.

Supported Versions

craco-less is tested with:

- react-scripts: ^3.2.0
- @craco/craco: ^5.5.0

Installation

First, follow the craco Installation Instructions to install the craco package, create a craco.config.js file, and modify the scripts in your package.json.

Then install craco-less:

`bash
$ yarn add craco-less

OR

$ npm i -S craco-less
`

Usage

Here is a complete craco.config.js configuration file that adds Less compilation to create-react-app:

`js
const CracoLessPlugin = require("craco-less");

module.exports = {
plugins: [{ plugin: CracoLessPlugin }],
};
`

Configuration

You can pass an options object to configure the loaders and plugins(configure _less_ and _less modules_ at the same time). You can also pass a modifyLessRule(or modifyLessModuleRule) callback to have full control over the Less webpack rule.

- options.styleLoaderOptions
- _Default:_ {}
- View the style-loader options
- options.cssLoaderOptions
- _Default:_ { importLoaders: 2 }
- View the css-loader options
- options.postcssLoaderOptions
- _Default:_ { ident: "postcss", plugins: () => [ ... ] }
- View the postcss-loader options
- options.lessLoaderOptions
- _Default:_ {}
- View the less-loader documentation
- View the Less options
- You must use "camelCase" instead of "dash-case", e.g. --source-map => sourceMap
- options.miniCssExtractPluginOptions _(only used in production)_
- _Default:_ {}
- View the mini-css-extract-plugin documentation
- options.modifyLessRule(lessRule, context)
- A callback function that receives two arguments: the webpack rule, and the context. You must return an updated rule object.
- lessRule:
- test: Regex (default: /\.less$/)
- exclude: Regex (default: /\.module\.less$/)
- use: Array of loaders and options.
- sideEffects: Boolean (default: true)
- context:
- env: "development" or "production"
- paths: An object with paths, e.g. appBuild, appPath, ownNodeModules
- options.modifyLessModuleRule(lessModuleRule, context)
- A callback function that receives two arguments: the webpack rule, and the context. You must return an updated rule object.
- lessModuleRule:
- test: Regex (default: /\.module\.less$/)
- use: Array of loaders and options.
- context:
- env: "development" or "production"
- paths: An object with paths, e.g. appBuild, appPath, ownNodeModules

For example, to configure less-loader:

`js
const CracoLessPlugin = require("craco-less");

module.exports = {
plugins: [
{
plugin: CracoLessPlugin,
options: {
lessLoaderOptions: {
lessOptions: {
modifyVars: {
"@primary-color": "#1DA57A",
"@link-color": "#1DA57A",
"@border-radius-base": "2px",
},
javascriptEnabled: true,
},
},
},
},
],
};
`

CSS / Less Modules

CSS / Less modules are enabled by default, and the default file suffix for _less modules_ is .module.less.

If your project is using typescript, please append the following code to ./src/react-app-env.d.ts

`ts
declare module "*.module.less" {
const classes: { readonly [key: string]: string };
export default classes;
}
`

You can use modifyLessModuleRule to configure the file suffix and loaders (css-loader, less-loader ...) for _less modules_.

For example:

`js
const CracoLessPlugin = require("craco-less");
const { loaderByName } = require("@craco/craco");

module.exports = {
plugins: [
{
plugin: CracoLessPlugin,
options: {
modifyLessRule(lessRule, context) {
// You have to exclude these file suffixes first,
// if you want to modify the less module's suffix
lessRule.exclude = /\.m\.less$/;
return lessRule;
},
modifyLessModuleRule(lessModuleRule, context) {
// Configure the file suffix
lessModuleRule.test = /\.m\.less$/;

// Configure the generated local ident name.
const cssLoader = lessModuleRule.use.find(loaderByName("css-loader"));
cssLoader.options.modules = {
localIdentName: "[local]_[hash:base64:5]",
};

return lessModuleRule;
},
},
},
],
};
`

#### CSS modules gotcha

There is a known problem with Less and CSS modules regarding relative file paths in url(...) statements. See this issue for an explanation.

> (Copied from the less-loader README.)

Further Configuration

If you need to configure anything else for the webpack build, take a look at the
Configuration Overview section in the craco README. You can use CracoLessPlugin while making other changes to babel and webpack, etc.

Contributing

Install dependencies:

`bash
$ yarn install

OR

$ npm install
`

Run tests:

`
$ yarn test
`

Before submitting a pull request, please check the following:

- All tests are passing
- Run yarn test
- 100% test coverage
- Coverage will be printed after running tests.
- Check the coverage results in your browser: open coverage/lcov-report/index.html
- No ESLint errors
- yarn lint
- All code is formatted with Prettier
- yarn format
- If you use VS Code, you should enable the formatOnSave option.
- Using the correct webpack version as a dependency
- yarn update_deps
- NOTE: The webpack dependency is needed to silence some annoying warnings from NPM.
This must always match the version from react-scripts.

Releasing a new version

- Make sure the "Supported Versions" section is updated at the top of the README.
- Check which files will be included in the NPM package:
- npm pack
- Update .npmignore to exclude any files.
- Release new version to NPM:
- npm publish`

License

MIT

Contributors

- ndbroadbent
- tux-tn
- alexandrtovmach
- cemremengu
- AO17
- Vovan-VE
- yifanwangsh
- swillis12
- nutgaard
- alexander-svendsen
- sgtsquiggs
- fanck0605