How to delete one directory and replace it with another one for web?

Question

I've replaced one package with another: dart:io on universal_io. And this showed me an error.

: Error: A value of type 'Directory/*1*/' can't be assigned to a variable of type 'Directory/*2*/'.
lib/…/sqlite/database.dart:42
 - 'Directory/*1*/' is from 'dart:io'.
- 'Directory/*2*/' is from 'package:universal_io/src/io_impl_js/directory.dart' ('/C:/Users/Asus/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/universal_io-1.0.1/lib/src/io_impl_js/directory.dart').
package:universal_io/…/io_impl_js/directory.dart:1
    io.Directory directory = await getApplicationDocumentsDirectory();

                             ^
Failed to compile application.