text: import * as FileUtil from 'fs/util/file-util';
  import * as DirOp from 'fs/operations/directory-operations';
  import { fromJS } from 'immutable';
  
  const DEFAULT_FILE_SYSTEM = {
    '/': FileUtil.makeDirectory()
  };
  
  /**
   * Creates an immutable data structure for a file system
   * @param  {object} jsFs a file system in a simple JavaScript object
   * @return {Map}         an immutable file system
   */
  export const create = (jsFs = DEFAULT_FILE_SYSTEM) => {
    return DirOp.fillGaps(fromJS(jsFs));
  };
  