minify.js

'use strict';

const Filter = require('broccoli-persistent-filter');
const CleanCSS = require('clean-css');
const { transform } = require('lightningcss');

function LightningCssFilter(inputTree) {
    Filter.call(this, inputTree, {
        extensions: ['css'],
        targetExtension: 'css',
        persist: true,
    });
}

LightningCssFilter.prototype = Object.create(Filter.prototype);
LightningCssFilter.prototype.constructor = LightningCssFilter;
LightningCssFilter.prototype.baseDir = function () {
    return __dirname;
};
LightningCssFilter.prototype.processString = function (css, relativePath) {
    // Some older Ember applications emit legacy nested at-rules in app CSS
    // that CleanCSS accepts. Modern third-party vendor CSS may use native CSS
    // nesting that CleanCSS 3 cannot parse, so minify each bundle accordingly.
    if (!relativePath.endsWith('vendor.css')) {
        const result = new CleanCSS().minify(css);
        if (result.errors.length) {
            throw new Error(result.errors.join('\n'));
        }
        return result.styles;
    }

    return transform({
        filename: relativePath,
        code: Buffer.from(css),
        minify: true,
    }).code.toString();
};

module.exports = function minifyWithLightningCss(tree) {
    return new LightningCssFilter(tree);
};

module.exports.LightningCssFilter = LightningCssFilter;