jest-css-modules-transform

Preprocessor css modules for Jest test framework

This preprocessor converts css files in modules like Webpack. If we have css files

.class1, .class2, .class3 {
    display: block;
}

Webpack will transfrom it to object.

{
    class1: 'class1', //value may be different. It depends of localIndentName property
    class2: 'class2',
    class3: 'class3',
}

In testing you need to mock all css modules to aviod exception. But use pure object {} for mocking is bad idea, because it makes wrong classNames in components. This preprocessor makes correct modules as if Webpack did.

Usage

In Jest config add option

"transform": {
  ".+\\.(css|styl|less|sass|scss)$": "<rootDir>/node_modules/jest-css-modules-transform"
},

It supports pure CSS, SCSS, SASS, STYLUS and LESS.

Options

You can save preproccessor options in file jest-css-modules-transform-config.js in root of your project(Where is the file package.json). You can pass options for your preprocessors.

example:

const path = require('path');  
const additionalResolvePath = path.resolve(__dirname, 'src', 'additional_modules');

module.exports = {
    sassConfig: {
        includePaths: [additionalResolvePath],
        precision: 5,
    },
    lessConfig: {
        paths: [additionalResolvePath],
    },
    stylusConfig: {
        paths: [additionalResolvePath],
    },
    postcssConfig: {
        plugins: [
            require('autoprefixer')({
                browsers: ['Chrome 68', 'Firefox 62', 'Safari 12']
            })
        ]
    },
};

For all preprocessor options see offical documentations for Sass, Less, Stylus.

Install