@americanexpress/purgecss-loader/loader.js

Webpack loader for removing unused CSS

/*
 * Copyright (c) 2018 American Express Travel Related Services Company, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

const { PurgeCSS } = require('purgecss');
const { getOptions } = require('loader-utils');

module.exports = async function purifyCssLoader(content) {
  const {
    paths, extractors = [], fontFace = false, keyframes = false, variables = false, safelist = [],
    blocklist = [],
  } = getOptions(this);
  const purgeCSSResult = await new PurgeCSS().purge({
    content: paths,
    css: [{ raw: content }],
    extractors,
    fontFace,
    keyframes,
    variables,
    safelist,
    blocklist,
  });
  return purgeCSSResult[0].css;
};