refactor: add static_methods.dart

Author: M.safaeian

common_utilities/lib/src/static_methods.dart

@@ -0,0 +1,9 @@
+import 'dart:convert';
+import 'dart:math';
+
+/// generate a secure random string
+String getRandomString(int len) {
+  var random = Random.secure();
+  var values = List<int>.generate(len, (i) => random.nextInt(255));
+  return base64UrlEncode(values);
+}

common_utilities/lib/src/string_utils.dart

@@ -1,6 +1,5 @@
-import 'dart:math';
 import 'package:intl/intl.dart';
-import 'dart:convert' show base64, base64UrlEncode, utf8;
+import 'dart:convert' show base64, utf8;
 
 class CommonStringUtils {
   static final String _exceptionTag = 'Exception on StringUtils : ';
@@ -322,11 +321,4 @@ class CommonStringUtils {
     if (_mainStr.isEmpty) return false;
     return Uri.tryParse(_mainStr)?.hasAbsolutePath ?? false;
   }
-
-  /// generate a secure random string
-  String getRandomString(int len) {
-    var random = Random.secure();
-    var values = List<int>.generate(len, (i) => random.nextInt(255));
-    return base64UrlEncode(values);
-  }
 }