Babel-plugin-css-to-js-transform

This Babel plugin finds all require and all import function for css files, and replace them with a new file with this name [filename]_css.js. It is keeps the the require and the import. In the file only replaces the file name with the new file name.

Then the transform generate a new file [filename]_css.js from [filename].css. It inserts class names as default export by css-modules with css-modules-require-hook package, and insert a getter _getCss function to the default object like some style loaders eg: isomorphic-style-loader

This plugin is based on the fantastic babel-plugin-css-modules-transform.

Why?

There are two reasons what the plugin was written:

1. The exists plugins don't support async plugins for postcss
2. Doesn't want insert class names to the file because it causes many duplicates and increases the bundle size.

These are especially interesting if you want to create a reusable high order component or module, and you want to add a css. When you create an end user type software use webpack and style-loaders.

Warning

This plugin is experimental, pull requests are welcome.

Example

/* srcDir/test_require.css */

.someClass {
    color: red;
    display: flex;
}

// srcDir/component.js
const styles = require("./test_import.css");

// outDir/test_require_css.js
"use strict";

Object.defineProperty(exports, "__esModule", {
    value: true
});

const tokens = {
    "someClass":"test_require_31cRH"
}; 

tokens._getCss = function () {
    return `/* imported from test_require.css */ .test_require_31cRH { color: red; display: flex; } `;
};

exports["default"] = tokens;

// outDir/component.js
var styles = require("dir/test_require_css.js")["default"];

Installation

npm install --save-dev babel-plugin-css-to-js-transform

Include plugin in .babelrc

{
    "plugins": ["css-to-js-transform"]
}

With custom options

module.exports = function (api, opts, env) {
    return {
        "plugins": [
            [
                require("babel-plugin-css-to-js-transform").default,
                {
                    cssModulesOptions: {
                        generateScopedName: "[name]_[hash:base64:5]",
                        //more options here: [css-modules-require-hook](https://github.com/css-modules/css-modules-require-hook)
                    },
                    alias: function alias({filePathOrModuleName, root, outDir, srcDir}) {
                        let relativeFromRoot = relative(root, filePathOrModuleName);
                        //if the processed css is exists the plugin read it from out folder.
                        if (relativeFromRoot.slice(0,3) === srcDir && existsSync(resolve(root, outDir + relativeFromRoot.slice(3)))){
                            relativeFromRoot = outDir + relativeFromRoot.slice(3)
                        }
                        return resolve(root, relativeFromRoot);
                    },
                    outDir: "dist"
                }
            ]
        ]
    }
}

Using a processor

When using this plugin with a processor, run it before this plugin running. This example show you how create a build function with postcss.

You can try it in test package from command line: babel-plugin-test build

// tools/build.js
const postcss = require("postcss");
const path = require("path");
const fs = require("fs");

/*...*/

/**Create a postcss runner*/
async function processCssFunction(processCss) {
    const plugins = [
        require("postcss-import")(),
        require("postcss-calc")(),
        require("pleeease-filters")(),
        require("pixrem")(),
        require("postcss-flexbugs-fixes")(),
        require("postcss-preset-env")({
            stage: 3,
            autoprefixer: { flexbox: "no-2009" },
        }),
    ];
    const runner = postcss(plugins)
    return await processCss({postcss, plugins, runner});
}

/**Create the processCss function what find all css files in src folder,
 * and it create generated css files to dist folder.
 * You can set up root, src and dist folders
 */

async function processCss(p = {}) {

    const {rootPath, distPath, srcPath} = getPaths(p)

    await processCssFunction(async function processCss({runner}) {

        function recursiveReadDir(entriesPath, o = {}) {
            fs.readdirSync(entriesPath).forEach(function(file){
                const curPath = path.resolve(entriesPath, file);
                if(fs.lstatSync(curPath).isDirectory()) {
                    recursiveReadDir(curPath, o);
                } else if (file.match(".css")){
                    const srcRelative = path.relative(srcPath, curPath);
                    const rootRelative = path.relative(rootPath, curPath);
                    o[srcRelative] = "./"+rootRelative;
                }
            });
        }

        const entries = {};
        recursiveReadDir(srcPath, entries);

        await Promise.all(Object.keys(entries).map(async function (relativePath) {
            return new Promise(async function(resolve, reject) {
                try {
                    const from = path.resolve(srcPath, relativePath);
                    const to = path.resolve(distPath, relativePath);
                    const css = fs.readFileSync(from);
                    const result = await runner.process(css, {from: from, to: to})
                    if (!fs.existsSync(path.dirname(to))){
                        fs.mkdirSync(path.dirname(to), { recursive: true });
                    }
                    if (!fs.existsSync(to)) {
                        fs.writeFileSync(to, result.css, function () {
                            return true;
                        })
                        console.log("Css processed: " + to)
                    } else {
                        console.log("File aready exists, run clean script or delete it manually before process css: " + to)
                    }
                    return resolve();
                } catch (e) {
                    return reject(e)
                }
            })
        }))

    })
}

/*...*/

/**
 * Build: first processCss, then babel
 **/
async function build(p = {}) {

    const {rootPath, distPath, srcPath} = getPaths(p)

    await clean(p);
    await processCss(p);
    const exec = require("child_process").exec;
    const execText = path.resolve(rootPath, "node_modules/.bin/babel") + " " + srcPath + " --presets=babel-preset-for-test --out-dir " + distPath;
    console.log("Run babel: " + execText);
    await exec(execText).stderr.pipe(process.stderr);
}

/*...*/

License

MIT