Function fixCjsTypes

scripts/fix-types.js:19–40

* Fixes the CommonJS type declarations file. * @param {string} fileName

(fileName)

 * @param {string} fileName
 */
async function fixCjsTypes(fileName) {
  let types = await fs.readFile(fileName, { encoding: 'utf-8' });

  // DOMPurify is exported as a default export, but rollup changes
  // it to be assigned to `module.exports`. We need to change the
  // type declarations to match what rollup changed it to. Remove
  // the "default" export from the `export { ... }` statement.
  let fixed = types.replace(', _default as default', '');

  // Verify that we actually removed something in case the
  // type declarations are different to what we expected.
  if (fixed === types) {
    throw new Error('Failed to fix CommonJS type declarations.');
  }

  // Append `export = _default;` to match the `module.exports = DOMPurify`
  // statement that Rollup creates. This can cause compilation errors
  // for certain configurations, so add a `@ts-ignore` comment before it.
  fixed += '\n// @ts-ignore\nexport = _default;\n';

  await fs.writeFile(fileName, fixed);
}