CSSTypingLoader.js

const fs = require('fs');

const banner =
  '// This code was generated by a tool.\n// Changes to this file may cause incorrect behavior and will be lost if\n// the code is regenerated.\n\n// tslint:disable\n';

module.exports = function (content, ...args) {
  const { resourcePath } = this;
  const callback = this.async();

  const matchClassNames = /^export var ([^=]+?) =/gm;

  let classNameResults = [];
  let declaration = '';
  let matchResult = null;
  console.log(resourcePath)
  while ((matchResult = matchClassNames.exec(content)) !== null) {
    classNameResults.push(matchResult[1]);
  }

  classNameResults.sort();

  declaration = classNameResults
    .map(className => `export declare const ${className}: string;\n`)
    .join('');

  fs.writeFile(
    `${resourcePath}.d.ts`,
    `${banner}\n${declaration}`,
    function () {
      callback(null, content, ...args);
    },
  );
};