From c77857dc864bd6018ae4aa240d882bea2e785952 Mon Sep 17 00:00:00 2001
From: Vincenzo Sarnataro <>
Date: Fri, 26 Mar 2021 15:39:56 +0100
Subject: [PATCH 01/11] add extensions for nullable Iterable add orEmpty
 extensions

---
 lib/src/iterable.dart | 83 +++++++++++++++++++++++--------------------
 1 file changed, 45 insertions(+), 38 deletions(-)

diff --git a/lib/src/iterable.dart b/lib/src/iterable.dart
index 364bd1a..d18c0bb 100644
--- a/lib/src/iterable.dart
+++ b/lib/src/iterable.dart
@@ -18,9 +18,51 @@ import 'package:quiver/iterables.dart';
 import 'data_stractures/stack.dart';
 import 'equality.dart';
 
-extension CollectionsExtensions<T> on Iterable<T> {
-  
+extension CollectionsNullableExtension<T> on Iterable<T>? {
+
+ /// Returns this Iterable if it's not `null` and the empty list otherwise.
+  Iterable<T> orEmpty() => this ?? Iterable<T>.empty();
+
+  ///Returns `true` if this nullable iterable is either null or empty.
+  bool get isEmptyOrNull => this?.isEmpty ?? true;
+
+  /// Returns `true` if at least one element matches the given [predicate].
+  bool any(bool predicate(T element)) {
+    if (this.isEmptyOrNull) return false;
+    for (final element in this.orEmpty()) if (predicate(element)) return true;
+    return false;
+  }
+
+  /// Return a list concatenates the output of the current list and another [iterable]
+  List<T> concatWithSingleList(Iterable<T> iterable) {
+    if (isEmptyOrNull || iterable.isEmptyOrNull) return [];
+
+    return <T>[...this.orEmpty(), ...iterable];
+  }
+
+  /// Return a list concatenates the output of the current list and multiple [iterables]
+  List<T> concatWithMultipleList(List<Iterable<T>> iterables) {
+    if (isEmptyOrNull || iterables.isEmptyOrNull) return [];
+    final list = iterables.toList(growable: false).expand((i) => i);
+    return <T>[...this.orEmpty(), ...list];
+  }
+
+  /// Zip is used to combine multiple iterables into a single list that contains
+  /// the combination of them two.
+  zip<T>(Iterable<T> iterable) sync* {
+    if (iterable.isEmptyOrNull) return;
+    final iterables = List<Iterable>.empty()
+      ..add(this.orEmpty())
+      ..add(iterable);
+
+    final iterators = iterables.map((e) => e.iterator).toList(growable: false);
+    while (iterators.every((e) => e.moveNext())) {
+      yield iterators.map((e) => e.current).toList(growable: false);
+    }
+  }
+}
 
+extension CollectionsExtensions<T> on Iterable<T> {
   ///Sorts elements in the array in-place according to natural sort order of the value returned by specified [selector] function.
   Iterable<T> sortBy<TKey>(
     TKey Function(T) keySelector, {
@@ -29,13 +71,6 @@ extension CollectionsExtensions<T> on Iterable<T> {
     return InternalOrderedIterable(this, keySelector, keyComparer, false);
   }
 
-  /// Returns `true` if at least one element matches the given [predicate].
-  bool any(bool predicate(T element)) {
-    if (this.isEmptyOrNull) return false;
-    for (final element in this) if (predicate(element)) return true;
-    return false;
-  }
-
   /// Convert iterable to set
   Set<T> toMutableSet() => Set.from(this);
 
@@ -124,7 +159,7 @@ extension CollectionsExtensions<T> on Iterable<T> {
   }
 
   // Retuns map operation as a List
-   List<E> mapList<E>(E f(T e)) => this.map(f).toList();
+  List<E> mapList<E>(E f(T e)) => this.map(f).toList();
 
   // Takes the first half of a list
   List<T> firstHalf() => take(halfLength).toList();
@@ -308,20 +343,6 @@ extension CollectionsExtensions<T> on Iterable<T> {
     return stack;
   }
 
-  bool get isEmptyOrNull => this == null || isEmpty;
-
-  /// Zip is used to combine multiple iterables into a single list that contains
-  /// the combination of them two.
-  zip<T>(Iterable<T> iterable) sync* {
-    if (iterable.isEmptyOrNull) return;
-    final iterables = List<Iterable>.empty()..add(this)..add(iterable);
-
-    final iterators = iterables.map((e) => e.iterator).toList(growable: false);
-    while (iterators.every((e) => e.moveNext())) {
-      yield iterators.map((e) => e.current).toList(growable: false);
-    }
-  }
-
   /// Splits the Iterable into chunks of the specified size
   ///
   /// example:
@@ -330,20 +351,6 @@ extension CollectionsExtensions<T> on Iterable<T> {
   /// ([1, 2, 3], [4, 5, 6], [7, 8, 9], [10])
   Iterable<List<T>> chunks(int size) => partition(this, size);
 
-  /// Return a list concatenates the output of the current list and another [iterable]
-  List<T> concatWithSingleList(Iterable<T> iterable) {
-    if (isEmptyOrNull || iterable.isEmptyOrNull) return [];
-
-    return <T>[...this, ...iterable];
-  }
-
-  /// Return a list concatenates the output of the current list and multiple [iterables]
-  List<T> concatWithMultipleList(List<Iterable<T>> iterables) {
-    if (isEmptyOrNull || iterables.isEmptyOrNull) return [];
-    final list = iterables.toList(growable: false).expand((i) => i);
-    return <T>[...this, ...list];
-  }
-
   /// Creates a Map instance in which the keys and values are computed from the iterable.
   Map<dynamic, dynamic> associate(key(element), value(element)) =>
       Map.fromIterable(this, key: key, value: value);

From 856d39cfa86e8a774220501510a43a5f7ebce4a5 Mon Sep 17 00:00:00 2001
From: Vincenzo Sarnataro <>
Date: Fri, 26 Mar 2021 15:40:07 +0100
Subject: [PATCH 02/11] add new test

---
 test/iterable_tests.dart | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/test/iterable_tests.dart b/test/iterable_tests.dart
index 54e4eda..6d6228f 100644
--- a/test/iterable_tests.dart
+++ b/test/iterable_tests.dart
@@ -194,5 +194,21 @@ main() {
       expect(Set.from([1, 2, 3, 4]).intersect(Set.from([3, 4, 5, 6])), [1, 2, 3, 4, 5, 6]);
       expect(Set.from([-1, -2, -3, 4]).intersect(Set.from([3, 4, 5, 6])), [-1, -2, -3, 4, 3, 5, 6]);
     });
+
+    test('orEmpty',(){
+      List<int>? list;
+      expect(list.orEmpty(), List<int>.empty());
+      list= [1,2,3];
+      expect(list.orEmpty(), [1,2,3]);
+    });
+
+    test('isEmptyOrNull',(){
+      List<int>? list;
+      expect(list.isEmptyOrNull, true);
+      list= [];
+      expect(list.isEmptyOrNull, true);
+      list= [1,2,3];
+      expect(list.isEmptyOrNull, false);
+    });
   });
 }

From abc0f5e0aca44449834d23d92f93e44d6b46c9b4 Mon Sep 17 00:00:00 2001
From: WingChan <wingchan@vgt-hk.net>
Date: Wed, 7 Apr 2021 16:41:53 +0800
Subject: [PATCH 03/11] fix: #17

---
 lib/src/iterable.dart | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/src/iterable.dart b/lib/src/iterable.dart
index 364bd1a..f5bb8b2 100644
--- a/lib/src/iterable.dart
+++ b/lib/src/iterable.dart
@@ -250,7 +250,7 @@ extension CollectionsExtensions<T> on Iterable<T> {
   /// 36 Ran
   List<T> distinctBy(predicate(T selector)) {
     final set = HashSet();
-    final list = List<T>.empty();
+    final List<T> list = [];
     toList().forEach((e) {
       final key = predicate(e);
       if (set.add(key)) {

From 9594012edc7dfa1094a0be4c032911835b413920 Mon Sep 17 00:00:00 2001
From: Idan Ayalon <bar.idan@gmail.com>
Date: Fri, 23 Apr 2021 23:15:25 +0300
Subject: [PATCH 04/11] added all, enum to stirng, wrapText

---
 README.md                                 |  2 ++
 lib/dart_extensions.dart                  |  2 +-
 lib/emum.dart                             | 13 +++++++++++
 lib/src/http.dart                         |  9 ++++----
 lib/src/int.dart                          |  1 +
 lib/src/iterable.dart                     | 21 +++++++++++++-----
 lib/src/{strings.dart => string_ext.dart} | 27 ++++++++++++++++++++++-
 lib/src/utils.dart                        |  1 +
 pubspec.yaml                              |  4 ++--
 test/enum_test.dart                       | 14 ++++++++++++
 test/iterable_tests.dart                  | 14 +++++++++---
 test/strings_test.dart                    |  7 +++++-
 12 files changed, 96 insertions(+), 19 deletions(-)
 create mode 100644 lib/emum.dart
 rename lib/src/{strings.dart => string_ext.dart} (91%)
 create mode 100644 test/enum_test.dart

diff --git a/README.md b/README.md
index 7072a60..5a95fbd 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,8 @@
   
  
 ## What New 
+* `Strings` -> `wrapString(int afterWords)` -> break the text in 2 lines (good to format titles and stuff like that)   
+* `enum` -> convert enum item into text. 
 * `SizedBox` extension - convert to percents 💪🏻
 * `Sound null-safety` added! 💪🏻
 * `BuildContext` extensions 💪🏻
diff --git a/lib/dart_extensions.dart b/lib/dart_extensions.dart
index 550c59b..ee7ebdc 100644
--- a/lib/dart_extensions.dart
+++ b/lib/dart_extensions.dart
@@ -30,6 +30,6 @@ export 'package:dart_extensions/src/iterable.dart';
 export 'package:dart_extensions/src/ranges.dart';
 export 'package:dart_extensions/src/search_algorithms.dart';
 export 'package:dart_extensions/src/sort_algorithms.dart';
-export 'package:dart_extensions/src/strings.dart';
+export 'package:dart_extensions/src/string_ext.dart';
 export 'package:dart_extensions/src/flutter/widgets.dart';
  
diff --git a/lib/emum.dart b/lib/emum.dart
new file mode 100644
index 0000000..a4ba19e
--- /dev/null
+++ b/lib/emum.dart
@@ -0,0 +1,13 @@
+extension EnumExt on dynamic {
+  static bool _isEnumItem(enumItem) {
+    final splitEnum = enumItem.toString().split('.');
+    return splitEnum.length > 1 && splitEnum[0] == enumItem.runtimeType.toString();
+  }
+
+  String convertToString({bool camelCase = false}) {
+    assert(this != null);
+    assert(_isEnumItem(this), '$this of type ${this.runtimeType.toString()} is not an enum item');
+    final temp = this.toString().split('.')[1];
+    return !camelCase ? temp : camelCaseToWords(temp);
+  } 
+}
diff --git a/lib/src/http.dart b/lib/src/http.dart
index be8101e..8095a29 100644
--- a/lib/src/http.dart
+++ b/lib/src/http.dart
@@ -12,8 +12,7 @@
  */
 
 import 'dart:convert' as convert;
-
-import 'package:dart_extensions/src/strings.dart';
+import '../src/string_ext.dart';
 import 'package:http/http.dart' as http;
 
 const _defaultHeaders = {"Content-type": "application/json"};
@@ -46,7 +45,7 @@ extension HttpExtensions on String {
   /// current string is www.mydomain.com
   /// endpoint param - user
   /// result request -> www.mydomain.com/user
-  Future<dynamic> httpPost(String endPoint,String json, [Map<String, String> headers = _defaultHeaders]) async {
+  Future<dynamic> httpPost(String endPoint, String json, [Map<String, String> headers = _defaultHeaders]) async {
     if (this.isEmptyOrNull) return;
 
     try {
@@ -66,7 +65,7 @@ extension HttpExtensions on String {
   /// current string is www.mydomain.com
   /// endpoint param - user
   /// result request -> www.mydomain.com/user
-  Future<dynamic> httpPut(String endPoint,String json, [Map<String, String> headers = _defaultHeaders]) async {
+  Future<dynamic> httpPut(String endPoint, String json, [Map<String, String> headers = _defaultHeaders]) async {
     if (this.isEmptyOrNull) return;
 
     try {
@@ -86,7 +85,7 @@ extension HttpExtensions on String {
   /// current string is www.mydomain.com
   /// endpoint param - user
   /// result request -> www.mydomain.com/user
-  Future<dynamic> httpDelete(String endPoint,{Map<String, String>? headers}) async {
+  Future<dynamic> httpDelete(String endPoint, {Map<String, String>? headers}) async {
     if (this.isEmptyOrNull) return;
 
     try {
diff --git a/lib/src/int.dart b/lib/src/int.dart
index e6dee5a..67339ae 100644
--- a/lib/src/int.dart
+++ b/lib/src/int.dart
@@ -23,6 +23,7 @@ extension IntExtensions on int {
     return this;
   }
 
+  // ignore: unnecessary_null_comparison
   bool get isNull => (this == null);
 
   /// Returns the absolute value
diff --git a/lib/src/iterable.dart b/lib/src/iterable.dart
index 364bd1a..4953d95 100644
--- a/lib/src/iterable.dart
+++ b/lib/src/iterable.dart
@@ -19,8 +19,6 @@ import 'data_stractures/stack.dart';
 import 'equality.dart';
 
 extension CollectionsExtensions<T> on Iterable<T> {
-  
-
   ///Sorts elements in the array in-place according to natural sort order of the value returned by specified [selector] function.
   Iterable<T> sortBy<TKey>(
     TKey Function(T) keySelector, {
@@ -124,7 +122,7 @@ extension CollectionsExtensions<T> on Iterable<T> {
   }
 
   // Retuns map operation as a List
-   List<E> mapList<E>(E f(T e)) => this.map(f).toList();
+  List<E> mapList<E>(E f(T e)) => this.map(f).toList();
 
   // Takes the first half of a list
   List<T> firstHalf() => take(halfLength).toList();
@@ -229,6 +227,18 @@ extension CollectionsExtensions<T> on Iterable<T> {
     return count;
   }
 
+  /// Returns `true` if all elements match the given predicate.
+  /// Example: 
+  /// [5, 19, 2].all(isEven), isFalse)
+  /// [6, 12, 2].all(isEven), isTrue)
+  bool all(bool predicate(T pred)?) {
+    for (var e in this) {
+      if (!predicate!(e))
+       return false;
+    }
+    return true;
+  }
+
   /// Returns a list containing only the elements from given collection having distinct keys.
   ///
   /// Basically it's just like distinct function but with a predicate
@@ -308,7 +318,7 @@ extension CollectionsExtensions<T> on Iterable<T> {
     return stack;
   }
 
-  bool get isEmptyOrNull => this == null || isEmpty;
+  bool get isEmptyOrNull => isEmpty;
 
   /// Zip is used to combine multiple iterables into a single list that contains
   /// the combination of them two.
@@ -345,8 +355,7 @@ extension CollectionsExtensions<T> on Iterable<T> {
   }
 
   /// Creates a Map instance in which the keys and values are computed from the iterable.
-  Map<dynamic, dynamic> associate(key(element), value(element)) =>
-      Map.fromIterable(this, key: key, value: value);
+  Map<dynamic, dynamic> associate(key(element), value(element)) => Map.fromIterable(this, key: key, value: value);
 
   /// Returns the first element matching the given [predicate], or `null`
   /// if element was not found.
diff --git a/lib/src/strings.dart b/lib/src/string_ext.dart
similarity index 91%
rename from lib/src/strings.dart
rename to lib/src/string_ext.dart
index 46ef638..04ce965 100644
--- a/lib/src/strings.dart
+++ b/lib/src/string_ext.dart
@@ -1,4 +1,5 @@
-/*
+
+  /*
  * Copyright 2020 Idan Ayalon. All rights reserved.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +26,30 @@ class Message {
 }
 
 extension StringExtensions on String? {
+
+    // Will add new line if the sentence is bigger the 2 words.
+  /// [afterWords] will add new line after the selected word
+  /// Example
+  /// 'Hi, my name is'.wrapString(2)
+  /// 
+  /// will print:
+  /// Hi, my
+  /// name is
+  
+  String wrapString(int afterWords) {
+    
+    final wordsArr = this?.split(' ') ?? [];
+
+    if (wordsArr.length > 2) {
+      final int middle = (this?.indexOf(wordsArr[afterWords]) ?? 0) - 1;
+      final prefix = this?.substring(0, middle);
+      final postfix = this?.substring(middle + 1);
+      return '$prefix\n$postfix';
+    }
+
+    return this ?? '';
+  }
+
   String generateMessageByGender({Gender? gender, Message? message}) => Intl.gender(gender.toString(),
       male: '$this ${message?.male}', female: '$this ${message?.female}', other: '$this ${message?.other}');
 
diff --git a/lib/src/utils.dart b/lib/src/utils.dart
index fad3b9e..f66707b 100644
--- a/lib/src/utils.dart
+++ b/lib/src/utils.dart
@@ -12,6 +12,7 @@
  */
 
 void checkNullError(Object o) {
+  // ignore: unnecessary_null_comparison
   if (o == null) {
     throw NullIteratorError();
   }
diff --git a/pubspec.yaml b/pubspec.yaml
index 44f084e..bfbcaf0 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: dart_extensions
 description: Set of method-extensions for dart that makes using framework in a much easier and clean way also adds additional functionality.
-version: 2.0.1
+version: 2.0.3
 documentation: https://github.com/droididan/dart_extentions
 homepage: https://github.com/droididan/dart_extentions
 
@@ -16,5 +16,5 @@ dependencies:
     sdk: flutter
 
 dev_dependencies:
-  test: ^1.16.7
+  test: 1.17.1 
   
\ No newline at end of file
diff --git a/test/enum_test.dart b/test/enum_test.dart
new file mode 100644
index 0000000..c72c118
--- /dev/null
+++ b/test/enum_test.dart
@@ -0,0 +1,14 @@
+import 'package:test/expect.dart';
+import 'package:test/test.dart';
+import '../lib/emum.dart';
+
+enum TestEnum { testValue1, testValue2, testValue3 }
+enum OtherEnumForTesting { helloImAnEnumValue }
+
+void main() {
+  test('it should convert enums to string', () {
+    expect(TestEnum.testValue1.convertToString(), 'testValue1');
+    expect(TestEnum.testValue2.convertToString(), 'testValue2');
+    expect(TestEnum.testValue3.convertToString(), 'testValue3');
+  });
+}
diff --git a/test/iterable_tests.dart b/test/iterable_tests.dart
index 54e4eda..0972bec 100644
--- a/test/iterable_tests.dart
+++ b/test/iterable_tests.dart
@@ -18,8 +18,16 @@ main() {
   final users = [User(22, "Ronit"), User(23, "Ronit"), User(22, "Oded"), User(32, "Shimi")];
 
   group('iterables', () {
+  
+    test('if all elements match the predicate', () {
+      final isEven = (x) => x % 2 == 0;
+      expect([5, 19, 2].all(isEven), isFalse);
+      expect([6, 12, 2].all(isEven), isTrue);
+      expect([].all(isEven), isTrue);
+    });
+
     test('mapList', () {
-      expect([3,4,5,6,7].mapList((item) => item.toDouble()), [3.0, 4.0, 5.0, 6.0, 7.0]);
+      expect([3, 4, 5, 6, 7].mapList((item) => item.toDouble()), [3.0, 4.0, 5.0, 6.0, 7.0]);
     });
 
     test('any', () {
@@ -28,8 +36,8 @@ main() {
       expect([].any((u) => u.name == 'Oded'), false);
     });
 
-    test("first or null", (){
-      final list= [1,45,6,9];
+    test("first or null", () {
+      final list = [1, 45, 6, 9];
       expect(null, list.firstWhere((element) => element == 7));
     });
 
diff --git a/test/strings_test.dart b/test/strings_test.dart
index 7386c58..06fef30 100644
--- a/test/strings_test.dart
+++ b/test/strings_test.dart
@@ -12,10 +12,15 @@
  */
 
 import 'package:test/test.dart';
-import 'package:dart_extensions/src/strings.dart';
+import 'package:dart_extensions/src/string_ext.dart';
 
 main() {
   group('strings', () {
+    test('it should wrap a string', () {
+      expect('one two three four'.wrapString(2), 'one two\nthree four');
+      expect('one two three four'.wrapString(3), 'one two three\nfour');
+    });
+
     test('validateEmail', () {
       expect('name@domain.com'.validateEmail(), true);
       expect('name@domain'.validateEmail(), false);

From 106871084fe01348d9ea38fdd2aac6f6b70b1674 Mon Sep 17 00:00:00 2001
From: Idan Ayalon <bar.idan@gmail.com>
Date: Fri, 23 Apr 2021 23:29:09 +0300
Subject: [PATCH 05/11] whereIndexed, all

---
 README.md                |   2 +
 lib/src/iterable.dart    |  43 ++++-
 test/iterable_tests.dart | 372 ++++++++++++++++++++-------------------
 3 files changed, 229 insertions(+), 188 deletions(-)

diff --git a/README.md b/README.md
index 5a95fbd..25aa039 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,8 @@
   
  
 ## What New 
+* `Iterables` -> `all` -> Returns `true` if all elements match the given predicate.
+* `Iterables` -> `whereIndexed` ->  Will retrun new [Iterable] with all elements that satisfy the predicate
 * `Strings` -> `wrapString(int afterWords)` -> break the text in 2 lines (good to format titles and stuff like that)   
 * `enum` -> convert enum item into text. 
 * `SizedBox` extension - convert to percents 💪🏻
diff --git a/lib/src/iterable.dart b/lib/src/iterable.dart
index 4953d95..e9c8121 100644
--- a/lib/src/iterable.dart
+++ b/lib/src/iterable.dart
@@ -18,6 +18,8 @@ import 'package:quiver/iterables.dart';
 import 'data_stractures/stack.dart';
 import 'equality.dart';
 
+typedef IndexedPredicate<T> = bool Function(int index, T);
+
 extension CollectionsExtensions<T> on Iterable<T> {
   ///Sorts elements in the array in-place according to natural sort order of the value returned by specified [selector] function.
   Iterable<T> sortBy<TKey>(
@@ -168,6 +170,9 @@ extension CollectionsExtensions<T> on Iterable<T> {
   /// var name = [].firstOrDefault["jack"]; // jack
   T firstOrDefault(T defaultValue) => firstOrNull ?? defaultValue;
 
+  /// Will retrun new [Iterable] with all elements that satisfy the predicate [predicate],
+  Iterable<T> whereIndexed(IndexedPredicate<T> predicate) => _IndexedWhereIterable(this, predicate);
+
   ///
   /// Performs the given action on each element on iterable, providing sequential index with the element.
   /// [item] the element on the current iteration
@@ -228,13 +233,12 @@ extension CollectionsExtensions<T> on Iterable<T> {
   }
 
   /// Returns `true` if all elements match the given predicate.
-  /// Example: 
+  /// Example:
   /// [5, 19, 2].all(isEven), isFalse)
   /// [6, 12, 2].all(isEven), isTrue)
   bool all(bool predicate(T pred)?) {
     for (var e in this) {
-      if (!predicate!(e))
-       return false;
+      if (!predicate!(e)) return false;
     }
     return true;
   }
@@ -369,3 +373,36 @@ extension CollectionsExtensions<T> on Iterable<T> {
     return null;
   }
 }
+
+// A lazy [Iterable] skip elements do **NOT** match the predicate [_f].
+class _IndexedWhereIterable<E> extends Iterable<E> {
+  final Iterable<E> _iterable;
+  final IndexedPredicate<E> _f;
+
+  _IndexedWhereIterable(this._iterable, this._f);
+
+  @override
+  Iterator<E> get iterator => _IndexedWhereIterator<E>(_iterable.iterator, _f);
+}
+
+/// [Iterator] for [_IndexedWhereIterable]
+class _IndexedWhereIterator<E> extends Iterator<E> {
+  final Iterator<E> _iterator;
+  final IndexedPredicate<E> _f;
+  int _index = 0;
+
+  _IndexedWhereIterator(this._iterator, this._f);
+
+  @override
+  bool moveNext() {
+    while (_iterator.moveNext()) {
+      if (_f(_index++, _iterator.current)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  @override
+  E get current => _iterator.current;
+}
diff --git a/test/iterable_tests.dart b/test/iterable_tests.dart
index 0972bec..cdac2ca 100644
--- a/test/iterable_tests.dart
+++ b/test/iterable_tests.dart
@@ -17,190 +17,192 @@ import 'package:test/test.dart';
 main() {
   final users = [User(22, "Ronit"), User(23, "Ronit"), User(22, "Oded"), User(32, "Shimi")];
 
-  group('iterables', () {
-  
-    test('if all elements match the predicate', () {
-      final isEven = (x) => x % 2 == 0;
-      expect([5, 19, 2].all(isEven), isFalse);
-      expect([6, 12, 2].all(isEven), isTrue);
-      expect([].all(isEven), isTrue);
-    });
-
-    test('mapList', () {
-      expect([3, 4, 5, 6, 7].mapList((item) => item.toDouble()), [3.0, 4.0, 5.0, 6.0, 7.0]);
-    });
-
-    test('any', () {
-      expect(users.any((u) => u.name == 'Oded'), true);
-      expect(users.any((u) => u.name == 'Not Exists'), false);
-      expect([].any((u) => u.name == 'Oded'), false);
-    });
-
-    test("first or null", () {
-      final list = [1, 45, 6, 9];
-      expect(null, list.firstWhere((element) => element == 7));
-    });
-
-    test('filter', () {
-      [null, 1, 2].where((n) => n == 2);
-      final listWithNull = [null, User(1, "r"), User(2, "t")];
-      final numberList = [1, 2, 3, 4, 5, 6];
-
-      expect(users.filter((u) => u.name == "Ronit"), [users[0], users[1]]);
-      expect(numberList.filter((n) => n > 4), [5, 6]);
-      expect(listWithNull.filter((u) => u?.name == "r"), [listWithNull[1]]);
-    });
-
-    test('filterNot', () {
-      final listWithNull = [null, User(1, "r"), User(2, "t")];
-      final numberList = [1, 2, 3, 4, 5, 6];
-
-      expect(listWithNull.filterNot((u) => u?.name == "t"), [listWithNull[1]]);
-      expect(numberList.filterNot((n) => n > 4), [1, 2, 3, 4]);
-    });
-
-    test('takeOnly', () {
-      expect([1, 2, 3, 4].takeOnly(1), [1]);
-      expect([1, 2, 3, 4].takeOnly(2), [1, 2]);
-      expect([1, 2, 3, 4].takeOnly(10), []);
-    });
-
-    test('drop', () {
-      expect([1, 2, 3, 4].drop(1), [2, 3, 4]);
-      expect([1, 2, 3, 4].drop(2), [3, 4]);
-      expect([1, 2, 3, 4].drop(5), []);
-    });
-
-    test('firstHalf', () {
-      expect([1, 2, 3, 4].firstHalf(), [1, 2]);
-    });
-
-    test('secondHalf', () {
-      expect([1, 2, 3, 4].secondHalf(), [3, 4]);
-    });
-
-    test('swap', () {
-      expect([1, 2, 3, 4].swap(0, 1), [2, 1, 3, 4]);
-    });
-
-    test('lastOrDefault', () {
-      expect([1, 2, 3, 4].lastOrDefault(999), 4);
-      expect([].lastOrDefault(999), 999);
-    });
-
-    test('firstOrDefault', () {
-      expect([1, 2, 3, 4].firstOrDefault(999), 1);
-      expect([].firstOrDefault(999), 999);
-    });
-
-    test('sortedDescending', () {
-      expect([1, 2, 3, 4].sortedDescending(), [4, 3, 2, 1]);
-    });
-
-    test('containsAll', () {
-      expect([1, 2, 3, 4].containsAll([1, 2, 5]), false);
-      expect([1, 2, 3, 4].containsAll([1, 2, 4]), true);
-      expect([].containsAll([1, 2, 4]), false);
-    });
-
-    test('containsAll', () {
-      expect([1, 2, 3, 4].containsAll([1, 2, 5]), false);
-      expect([1, 2, 3, 4].containsAll([1, 2, 4]), true);
-      expect([].containsAll([1, 2, 4]), false);
-    });
-
-    test('containsAll', () {
-      expect(users.count((u) => u.age == 22), 2);
-      expect(users.count((u) => u.name == "Ronit"), 2);
-      expect(users.count((u) => u.name == "Bin"), 0);
-    });
-
-    test('distinctBy', () {
-      final expected = users.distinctBy((u) => u.age);
-      expect(users.distinctBy((u) => u.age), expected);
-    });
-
-    test('subtract', () {
-      expect([1, 2, 3, 4].subtract([3, 4]), [1, 2]);
-      expect([1, 2, 3, 4].subtract([1, 2, 3, 4]), []);
-      expect([1, 2, 3, 4].subtract([1, 2]), [3, 4]);
-    });
-
-    test('toStack', () {
-      var stack = [1, 2, 3, 4].toStack();
-      expect(stack.pop(), 4);
-      expect(stack.top(), 3);
-      expect(stack.pop(), 3);
-      expect(stack.top(), 2);
-    });
-
-    test('concatWithSingleList', () {
-      expect([1, 2, 3, 4].concatWithSingleList([5, 6, 7, 8, 9, 10, 11]), [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
-      expect([1, 2, 3, 4].concatWithSingleList([]), []);
-      expect([].concatWithSingleList([5, 6, 7, 8, 9, 10, 11]), []);
-    });
-
-    test('concatWithMultipleList', () {
-      final listOfLists = [
-        [5, 6, 7],
-        [8, 9, 10]
-      ];
-      expect([1, 2, 3, 4].concatWithMultipleList(listOfLists), [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
-      expect([1, 2, 3, 4].concatWithMultipleList([[], []]), [1, 2, 3, 4]);
-      expect([].concatWithMultipleList(listOfLists), []);
-    });
-
-    test('zip', () {
-      final expectedResult = [
-        [1, 2],
-        [3, 4],
-        [5, 6]
-      ];
-      expect([1, 3, 5].zip([2, 4, 6]), expectedResult);
-      expect([1, 3, 5].zip([2, 4, 6, 7, 8]), expectedResult);
-    });
-
-    test('associate', () {
-      final users = [User(33, "Miki"), User(45, "Anna"), User(19, "Amit")];
-      expect(users.associate((k) => k.name, (e) => e.age), {'Miki': 33, 'Anna': 45, 'Amit': 19});
-    });
-
-    test('find', () {
-      final users = [User(22, "Ronit"), User(23, "Ronit"), User(22, "Oded"), User(32, "Shimi")];
-      expect(users.find((u) => u.name == "Ronit"), users.first);
-      expect(users.find((u) => u.name == "Oded"), users[2]);
-      expect(users.find((u) => u.name == "Not Exists Name"), null);
-      expect(users.find((u) => u.age == 32), users.last);
-      expect(users.find((u) => u.age == 31), null);
-    });
-
-    test('gruopBy by age', () {
-      final expected = {
-        22: [users[0], users[2]],
-        23: [users[1]],
-        32: [users[3]]
-      };
-
-      expect(users.groupBy((User u) => u.age), expected);
-    });
-
-    test('gourpBy by name', () {
-      final expected = {
-        'Ronit': [users[0], users[1]],
-        'Oded': [users[2]],
-        'Shimi': [users[3]]
-      };
-      expect(users.groupBy((User u) => u.name), expected);
-    });
-
-    test('toMutableSet', () {
-      expect([1, 1, 1, 1, 2, 3, 4].toMutableSet(), [1, 2, 3, 4]);
-      expect(["a", "b", "a"].toMutableSet(), ["a", "b"]);
-    });
-
-    test('intersect', () {
-      expect(Set.from([1, 2, 3, 4]).intersect(Set.from([3, 4, 5, 6])), [1, 2, 3, 4, 5, 6]);
-      expect(Set.from([-1, -2, -3, 4]).intersect(Set.from([3, 4, 5, 6])), [-1, -2, -3, 4, 3, 5, 6]);
-    });
+  test('result of whereIndex', () {
+    final result = users.whereIndexed((index, _) => index == 2);
+    expect(result, [User(22, "Oded")]);
+  });
+
+  test('if all elements match the predicate', () {
+    final isEven = (x) => x % 2 == 0;
+    expect([5, 19, 2].all(isEven), isFalse);
+    expect([6, 12, 2].all(isEven), isTrue);
+    expect([].all(isEven), isTrue);
+  });
+
+  test('mapList', () {
+    expect([3, 4, 5, 6, 7].mapList((item) => item.toDouble()), [3.0, 4.0, 5.0, 6.0, 7.0]);
+  });
+
+  test('any', () {
+    expect(users.any((u) => u.name == 'Oded'), true);
+    expect(users.any((u) => u.name == 'Not Exists'), false);
+    expect([].any((u) => u.name == 'Oded'), false);
+  });
+
+  test("first or null", () {
+    final list = [1, 45, 6, 9];
+    expect(null, list.firstWhere((element) => element == 7));
+  });
+
+  test('filter', () {
+    [null, 1, 2].where((n) => n == 2);
+    final listWithNull = [null, User(1, "r"), User(2, "t")];
+    final numberList = [1, 2, 3, 4, 5, 6];
+
+    expect(users.filter((u) => u.name == "Ronit"), [users[0], users[1]]);
+    expect(numberList.filter((n) => n > 4), [5, 6]);
+    expect(listWithNull.filter((u) => u?.name == "r"), [listWithNull[1]]);
+  });
+
+  test('filterNot', () {
+    final listWithNull = [null, User(1, "r"), User(2, "t")];
+    final numberList = [1, 2, 3, 4, 5, 6];
+
+    expect(listWithNull.filterNot((u) => u?.name == "t"), [listWithNull[1]]);
+    expect(numberList.filterNot((n) => n > 4), [1, 2, 3, 4]);
+  });
+
+  test('takeOnly', () {
+    expect([1, 2, 3, 4].takeOnly(1), [1]);
+    expect([1, 2, 3, 4].takeOnly(2), [1, 2]);
+    expect([1, 2, 3, 4].takeOnly(10), []);
+  });
+
+  test('drop', () {
+    expect([1, 2, 3, 4].drop(1), [2, 3, 4]);
+    expect([1, 2, 3, 4].drop(2), [3, 4]);
+    expect([1, 2, 3, 4].drop(5), []);
+  });
+
+  test('firstHalf', () {
+    expect([1, 2, 3, 4].firstHalf(), [1, 2]);
+  });
+
+  test('secondHalf', () {
+    expect([1, 2, 3, 4].secondHalf(), [3, 4]);
+  });
+
+  test('swap', () {
+    expect([1, 2, 3, 4].swap(0, 1), [2, 1, 3, 4]);
+  });
+
+  test('lastOrDefault', () {
+    expect([1, 2, 3, 4].lastOrDefault(999), 4);
+    expect([].lastOrDefault(999), 999);
+  });
+
+  test('firstOrDefault', () {
+    expect([1, 2, 3, 4].firstOrDefault(999), 1);
+    expect([].firstOrDefault(999), 999);
+  });
+
+  test('sortedDescending', () {
+    expect([1, 2, 3, 4].sortedDescending(), [4, 3, 2, 1]);
+  });
+
+  test('containsAll', () {
+    expect([1, 2, 3, 4].containsAll([1, 2, 5]), false);
+    expect([1, 2, 3, 4].containsAll([1, 2, 4]), true);
+    expect([].containsAll([1, 2, 4]), false);
+  });
+
+  test('containsAll', () {
+    expect([1, 2, 3, 4].containsAll([1, 2, 5]), false);
+    expect([1, 2, 3, 4].containsAll([1, 2, 4]), true);
+    expect([].containsAll([1, 2, 4]), false);
+  });
+
+  test('containsAll', () {
+    expect(users.count((u) => u.age == 22), 2);
+    expect(users.count((u) => u.name == "Ronit"), 2);
+    expect(users.count((u) => u.name == "Bin"), 0);
+  });
+
+  test('distinctBy', () {
+    final expected = users.distinctBy((u) => u.age);
+    expect(users.distinctBy((u) => u.age), expected);
+  });
+
+  test('subtract', () {
+    expect([1, 2, 3, 4].subtract([3, 4]), [1, 2]);
+    expect([1, 2, 3, 4].subtract([1, 2, 3, 4]), []);
+    expect([1, 2, 3, 4].subtract([1, 2]), [3, 4]);
+  });
+
+  test('toStack', () {
+    var stack = [1, 2, 3, 4].toStack();
+    expect(stack.pop(), 4);
+    expect(stack.top(), 3);
+    expect(stack.pop(), 3);
+    expect(stack.top(), 2);
+  });
+
+  test('concatWithSingleList', () {
+    expect([1, 2, 3, 4].concatWithSingleList([5, 6, 7, 8, 9, 10, 11]), [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    expect([1, 2, 3, 4].concatWithSingleList([]), []);
+    expect([].concatWithSingleList([5, 6, 7, 8, 9, 10, 11]), []);
+  });
+
+  test('concatWithMultipleList', () {
+    final listOfLists = [
+      [5, 6, 7],
+      [8, 9, 10]
+    ];
+    expect([1, 2, 3, 4].concatWithMultipleList(listOfLists), [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+    expect([1, 2, 3, 4].concatWithMultipleList([[], []]), [1, 2, 3, 4]);
+    expect([].concatWithMultipleList(listOfLists), []);
+  });
+
+  test('zip', () {
+    final expectedResult = [
+      [1, 2],
+      [3, 4],
+      [5, 6]
+    ];
+    expect([1, 3, 5].zip([2, 4, 6]), expectedResult);
+    expect([1, 3, 5].zip([2, 4, 6, 7, 8]), expectedResult);
+  });
+
+  test('associate', () {
+    final users = [User(33, "Miki"), User(45, "Anna"), User(19, "Amit")];
+    expect(users.associate((k) => k.name, (e) => e.age), {'Miki': 33, 'Anna': 45, 'Amit': 19});
+  });
+
+  test('find', () {
+    final users = [User(22, "Ronit"), User(23, "Ronit"), User(22, "Oded"), User(32, "Shimi")];
+    expect(users.find((u) => u.name == "Ronit"), users.first);
+    expect(users.find((u) => u.name == "Oded"), users[2]);
+    expect(users.find((u) => u.name == "Not Exists Name"), null);
+    expect(users.find((u) => u.age == 32), users.last);
+    expect(users.find((u) => u.age == 31), null);
+  });
+
+  test('gruopBy by age', () {
+    final expected = {
+      22: [users[0], users[2]],
+      23: [users[1]],
+      32: [users[3]]
+    };
+
+    expect(users.groupBy((User u) => u.age), expected);
+  });
+
+  test('gourpBy by name', () {
+    final expected = {
+      'Ronit': [users[0], users[1]],
+      'Oded': [users[2]],
+      'Shimi': [users[3]]
+    };
+    expect(users.groupBy((User u) => u.name), expected);
+  });
+
+  test('toMutableSet', () {
+    expect([1, 1, 1, 1, 2, 3, 4].toMutableSet(), [1, 2, 3, 4]);
+    expect(["a", "b", "a"].toMutableSet(), ["a", "b"]);
+  });
+
+  test('intersect', () {
+    expect(Set.from([1, 2, 3, 4]).intersect(Set.from([3, 4, 5, 6])), [1, 2, 3, 4, 5, 6]);
+    expect(Set.from([-1, -2, -3, 4]).intersect(Set.from([3, 4, 5, 6])), [-1, -2, -3, 4, 3, 5, 6]);
   });
 }

From be4a9e95453c8ba88270418941f6355deeb42d80 Mon Sep 17 00:00:00 2001
From: Idan Ayalon <bar.idan@gmail.com>
Date: Fri, 23 Apr 2021 23:32:02 +0300
Subject: [PATCH 06/11] badge commit

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 25aa039..5131356 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
   
-[![](https://img.shields.io/badge/ver-2.0.1-brightgreen)](https://github.com/droididan/dart_extentions)   ![](https://img.shields.io/badge/Code%20Coverage-96%25-green) ![](https://img.shields.io/badge/Bitrise-Pass-green)  
+[![](https://img.shields.io/badge/ver-2.0.3-brightgreen)](https://github.com/droididan/dart_extentions)   ![](https://img.shields.io/badge/Code%20Coverage-96%25-green) ![](https://img.shields.io/badge/Bitrise-Pass-green)  
   
  
 ## What New 

From 4efcce90519d4c1ef9ed6ee3e9157e5c13f9fc84 Mon Sep 17 00:00:00 2001
From: Idan Ayalon <bar.idan@gmail.com>
Date: Fri, 23 Apr 2021 23:33:18 +0300
Subject: [PATCH 07/11] badge commit

---
 README.md    | 2 +-
 pubspec.yaml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 5131356..611513e 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
   
-[![](https://img.shields.io/badge/ver-2.0.3-brightgreen)](https://github.com/droididan/dart_extentions)   ![](https://img.shields.io/badge/Code%20Coverage-96%25-green) ![](https://img.shields.io/badge/Bitrise-Pass-green)  
+[![](https://img.shields.io/badge/ver-2.0.4-brightgreen)](https://github.com/droididan/dart_extentions)   ![](https://img.shields.io/badge/Code%20Coverage-96%25-green) ![](https://img.shields.io/badge/Bitrise-Pass-green)  
   
  
 ## What New 
diff --git a/pubspec.yaml b/pubspec.yaml
index bfbcaf0..afe733f 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: dart_extensions
 description: Set of method-extensions for dart that makes using framework in a much easier and clean way also adds additional functionality.
-version: 2.0.3
+version: 2.0.4
 documentation: https://github.com/droididan/dart_extentions
 homepage: https://github.com/droididan/dart_extentions
 

From 813ba3d7d472b1d3d5c73cdb463bfc284c2d3dc6 Mon Sep 17 00:00:00 2001
From: Idan Ayalon <bar.idan@gmail.com>
Date: Wed, 26 May 2021 12:14:58 +0300
Subject: [PATCH 08/11] version 2.0.5

---
 CHANGELOG.md                  |  17 ++++
 README.md                     |  30 +++---
 lib/src/flutter/duration.dart |  14 +++
 lib/src/iterable.dart         |  74 ++++++++-------
 lib/src/string_ext.dart       | 170 ++++++++++++++++++++++++++++++----
 pubspec.yaml                  |   2 +-
 6 files changed, 237 insertions(+), 70 deletions(-)
 create mode 100644 lib/src/flutter/duration.dart

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b4f12a3..a1e4bca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,20 @@
+## [2.0.5] - 11/03/21
+- `delay` await 3.seconds.delay(() { some code }
+- `added getTextSize` - A good use-case will be drawing a divider with the exect width of the text above it.
+- `isVideo` - Checks if string is an video file.
+- `isAudio` - Checks if string is an audio file.
+- `isImage` - Checks if string is an image file.
+- `isNumericOnly` - Check if the string has any number in it.
+- `isAlphabetOnly` - Checks if string consist only Alphabet. (No Whitespace)
+- `hasCapitalletter` - Checks if string contains at least one Capital Letter.
+- `isHTML` - Checks if string is an html file. 
+- `isEmail` -  Checks if string is email..
+- `isPhoneNumber` -  Checks if string is phone number, good for login checks.
+- `isUsername` - Checks if string is a valid username, good for login checks.
+- `isCurrency` - Checks if string is Currency.
+- `isPalindrom` - Checks if string is Palindrom. (good to know for interviews as well)
+
+
 ## [2.0.0] - 11/03/21
 - `Support flutter 2`
 - `Support null safety`
diff --git a/README.md b/README.md
index 611513e..69b5606 100644
--- a/README.md
+++ b/README.md
@@ -1,21 +1,23 @@
   
-[![](https://img.shields.io/badge/ver-2.0.4-brightgreen)](https://github.com/droididan/dart_extentions)   ![](https://img.shields.io/badge/Code%20Coverage-96%25-green) ![](https://img.shields.io/badge/Bitrise-Pass-green)  
+[![](https://img.shields.io/badge/ver-2.0.5-green)](https://github.com/droididan/dart_extentions)   ![](https://img.shields.io/badge/Code%20Coverage-96%25-green) ![](https://img.shields.io/badge/Bitrise-Pass-green)  
   
  
 ## What New 
-* `Iterables` -> `all` -> Returns `true` if all elements match the given predicate.
-* `Iterables` -> `whereIndexed` ->  Will retrun new [Iterable] with all elements that satisfy the predicate
-* `Strings` -> `wrapString(int afterWords)` -> break the text in 2 lines (good to format titles and stuff like that)   
-* `enum` -> convert enum item into text. 
-* `SizedBox` extension - convert to percents 💪🏻
-* `Sound null-safety` added! 💪🏻
-* `BuildContext` extensions 💪🏻
-* `List<Widget>` extensions 💪🏻
-* `Text` extensions 💪🏻
-* `Icon` extensions 💪🏻
-* `.sortBy` [0.3.5] Sorts elements in the array in-place according to natural sort order of the value returned by specified selector function.
-* `.withTooltip` Tooltips improve the accessibility of visual widgets by proving a textual representation of the widget
-
+* `Iterables` -> `all` -> Returns `true` if all elements match the given  
+* `isVideo` - Checks if string is an video file.
+* `isAudio` - Checks if string is an audio file.
+* `isImage` - Checks if string is an image file.
+* `isNumericOnly` - Check if the string has any number in it.
+* `isAlphabetOnly` - Checks if string consist only Alphabet. (No Whitespace)
+* `hasCapitalletter` - Checks if string contains at least one Capital Letter.
+* `isHTML` - Checks if string is an html file. 
+* `isEmail` -  Checks if string is email..
+* `isPhoneNumber` -  Checks if string is phone number, good for login checks.
+* `isUsername` - Checks if string is a valid username, good for login checks.
+* `isCurrency` - Checks if string is Currency.
+* `isPalindrom` - Checks if string is Palindrom. (good to know for interviews 
+
+as well)
 Why Method Extensions? When you’re using someone else’s API or when you implement a library that’s widely used, it’s often impractical or impossible to change the API. But you might still want to add some functionality.  
   
   *let me know if you want something specific or you found a bug at bar.idan@gmail.com*  
diff --git a/lib/src/flutter/duration.dart b/lib/src/flutter/duration.dart
new file mode 100644
index 0000000..4a59735
--- /dev/null
+++ b/lib/src/flutter/duration.dart
@@ -0,0 +1,14 @@
+import 'dart:async';
+
+extension DurationExt on Duration {
+  /// Utility to delay some callback (or code execution).
+  ///
+  /// Sample:
+  /// ```
+  ///   await 3.seconds.delay(() {
+  ///           ....
+  ///   }
+  ///
+  ///```
+  Future delay([FutureOr callback()?]) async => Future.delayed(this, callback);
+}
diff --git a/lib/src/iterable.dart b/lib/src/iterable.dart
index db9a9a7..249b10b 100644
--- a/lib/src/iterable.dart
+++ b/lib/src/iterable.dart
@@ -21,6 +21,45 @@ import 'equality.dart';
 typedef IndexedPredicate<T> = bool Function(int index, T);
 
 extension CollectionsExtensions<T> on Iterable<T> {
+  /// Returns this Iterable if it's not `null` and the empty list otherwise.
+  Iterable<T> orEmpty() => this;
+
+  ///Returns `true` if this nullable iterable is either null or empty.
+  bool get isEmptyOrNull => this.isEmpty;
+
+  /// Returns `true` if at least one element matches the given [predicate].
+  bool any(bool predicate(T element)) {
+    if (this.isEmptyOrNull) return false;
+    for (final element in this.orEmpty()) if (predicate(element)) return true;
+    return false;
+  }
+
+  /// Return a list concatenates the output of the current list and another [iterable]
+  List<T> concatWithSingleList(Iterable<T> iterable) {
+    if (isEmptyOrNull || iterable.isEmptyOrNull) return [];
+
+    return <T>[...this.orEmpty(), ...iterable];
+  }
+
+  /// Return a list concatenates the output of the current list and multiple [iterables]
+  List<T> concatWithMultipleList(List<Iterable<T>> iterables) {
+    if (isEmptyOrNull || iterables.isEmptyOrNull) return [];
+    final list = iterables.toList(growable: false).expand((i) => i);
+    return <T>[...this.orEmpty(), ...list];
+  }
+
+  /// Zip is used to combine multiple iterables into a single list that contains
+  /// the combination of them two.
+  zip<T>(Iterable<T> iterable) sync* {
+    if (iterable.isEmptyOrNull) return;
+    final iterables = List<Iterable>.empty()..add(this.orEmpty())..add(iterable);
+
+    final iterators = iterables.map((e) => e.iterator).toList(growable: false);
+    while (iterators.every((e) => e.moveNext())) {
+      yield iterators.map((e) => e.current).toList(growable: false);
+    }
+  }
+
   ///Sorts elements in the array in-place according to natural sort order of the value returned by specified [selector] function.
   Iterable<T> sortBy<TKey>(
     TKey Function(T) keySelector, {
@@ -29,13 +68,6 @@ extension CollectionsExtensions<T> on Iterable<T> {
     return InternalOrderedIterable(this, keySelector, keyComparer, false);
   }
 
-  /// Returns `true` if at least one element matches the given [predicate].
-  bool any(bool predicate(T element)) {
-    if (this.isEmptyOrNull) return false;
-    for (final element in this) if (predicate(element)) return true;
-    return false;
-  }
-
   /// Convert iterable to set
   Set<T> toMutableSet() => Set.from(this);
 
@@ -322,20 +354,6 @@ extension CollectionsExtensions<T> on Iterable<T> {
     return stack;
   }
 
-  bool get isEmptyOrNull => isEmpty;
-
-  /// Zip is used to combine multiple iterables into a single list that contains
-  /// the combination of them two.
-  zip<T>(Iterable<T> iterable) sync* {
-    if (iterable.isEmptyOrNull) return;
-    final iterables = List<Iterable>.empty()..add(this)..add(iterable);
-
-    final iterators = iterables.map((e) => e.iterator).toList(growable: false);
-    while (iterators.every((e) => e.moveNext())) {
-      yield iterators.map((e) => e.current).toList(growable: false);
-    }
-  }
-
   /// Splits the Iterable into chunks of the specified size
   ///
   /// example:
@@ -344,20 +362,6 @@ extension CollectionsExtensions<T> on Iterable<T> {
   /// ([1, 2, 3], [4, 5, 6], [7, 8, 9], [10])
   Iterable<List<T>> chunks(int size) => partition(this, size);
 
-  /// Return a list concatenates the output of the current list and another [iterable]
-  List<T> concatWithSingleList(Iterable<T> iterable) {
-    if (isEmptyOrNull || iterable.isEmptyOrNull) return [];
-
-    return <T>[...this, ...iterable];
-  }
-
-  /// Return a list concatenates the output of the current list and multiple [iterables]
-  List<T> concatWithMultipleList(List<Iterable<T>> iterables) {
-    if (isEmptyOrNull || iterables.isEmptyOrNull) return [];
-    final list = iterables.toList(growable: false).expand((i) => i);
-    return <T>[...this, ...list];
-  }
-
   /// Creates a Map instance in which the keys and values are computed from the iterable.
   Map<dynamic, dynamic> associate(key(element), value(element)) => Map.fromIterable(this, key: key, value: value);
 
diff --git a/lib/src/string_ext.dart b/lib/src/string_ext.dart
index 04ce965..85f81ed 100644
--- a/lib/src/string_ext.dart
+++ b/lib/src/string_ext.dart
@@ -1,5 +1,4 @@
-
-  /*
+/*
  * Copyright 2020 Idan Ayalon. All rights reserved.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -12,6 +11,7 @@
  * limitations under the License.
  */
 
+import 'package:flutter/material.dart';
 import 'package:intl/intl.dart';
 
 enum Gender { male, female }
@@ -19,25 +19,151 @@ enum Gender { male, female }
 class Message {
   final String male, female, other;
 
-  Message({required this.male,required this.female,required this.other})
+  Message({required this.male, required this.female, required this.other})
       : assert(male.isEmptyOrNull),
         assert(female.isEmptyOrNull),
         assert(other.isEmptyOrNull);
 }
 
 extension StringExtensions on String? {
+  bool isNull(dynamic value) => value == null;
+
+  /// Returns whether a dynamic value PROBABLY
+  /// has the isEmpty getter/method by checking
+  /// standard dart types that contains it.
+  ///
+  /// This is here to for the 'DRY'
+  bool? _isEmpty(dynamic value) {
+    if (value is String) {
+      return value.toString().trim().isEmpty;
+    }
+    if (value is Iterable || value is Map) {
+      return value.isEmpty as bool?;
+    }
+    return false;
+  }
+
+
+
+  /// Checks if string is a valid username.
+  bool isUsername(String s) => hasMatch(s, r'^[a-zA-Z0-9][a-zA-Z0-9_.]+[a-zA-Z0-9]$');
+
+  /// Checks if string is Palindrom.
+  bool isPalindrom(String string) {
+    final cleanString = string.toLowerCase().replaceAll(RegExp(r"\s+"), '').replaceAll(RegExp(r"[^0-9a-zA-Z]+"), "");
+
+    for (var i = 0; i < cleanString.length; i++) {
+      if (cleanString[i] != cleanString[cleanString.length - i - 1]) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  /// Checks if string is Currency.
+  bool isCurrency(String s) => hasMatch(s,
+      r'^(S?\$|\₩|Rp|\¥|\€|\₹|\₽|fr|R\$|R)?[ ]?[-]?([0-9]{1,3}[,.]([0-9]{3}[,.])*[0-9]{3}|[0-9]+)([,.][0-9]{1,2})?( ?(USD?|AUD|NZD|CAD|CHF|GBP|CNY|EUR|JPY|IDR|MXN|NOK|KRW|TRY|INR|RUB|BRL|ZAR|SGD|MYR))?$');
+
+  /// Checks if string is phone number.
+  bool isPhoneNumber(String s) {
+    if (s.length > 16 || s.length < 9) return false;
+    return hasMatch(s, r'^[+]*[(]{0,1}[0-9]{1,4}[)]{0,1}[-\s\./0-9]*$');
+  }
+
+  /// Checks if string is email.
+  bool isEmail(String s) => hasMatch(s,
+      r'^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$');
+
+  /// Checks if string is an html file.
+  bool isHTML(String filePath) {
+    return filePath.toLowerCase().endsWith(".html");
+  }
+
+    /// Checks if string is an video file.
+  bool isVideo(String filePath) {
+    var ext = filePath.toLowerCase();
+
+    return ext.endsWith(".mp4") ||
+        ext.endsWith(".avi") ||
+        ext.endsWith(".wmv") ||
+        ext.endsWith(".rmvb") ||
+        ext.endsWith(".mpg") ||
+        ext.endsWith(".mpeg") ||
+        ext.endsWith(".3gp");
+  }
+  
+  /// Checks if string is an audio file.
+  bool isAudio(String filePath) {
+    final ext = filePath.toLowerCase();
+
+    return ext.endsWith(".mp3") ||
+        ext.endsWith(".wav") ||
+        ext.endsWith(".wma") ||
+        ext.endsWith(".amr") ||
+        ext.endsWith(".ogg");
+  }
+
+  /// Checks if string is an image file.
+  bool isImage(String filePath) {
+    final ext = filePath.toLowerCase();
+
+    return ext.endsWith(".jpg") ||
+        ext.endsWith(".jpeg") ||
+        ext.endsWith(".png") ||
+        ext.endsWith(".gif") ||
+        ext.endsWith(".bmp");
+  }
+
+  bool hasMatch(String? value, String pattern) {
+    return (value == null) ? false : RegExp(pattern).hasMatch(value);
+  }
+
+  // Check if the string has any number in it, not accepting double, so don't
+  // use "."
+  isNumericOnly(String s) => hasMatch(s, r'^\d+$');
+
+  /// Checks if string consist only Alphabet. (No Whitespace)
+  bool isAlphabetOnly(String s) => hasMatch(s, r'^[a-zA-Z]+$');
+
+  /// Checks if string contains at least one Capital Letter
+  bool hasCapitalletter(String s) => hasMatch(s, r'[A-Z]');
+
+  /// Checks if data is null or blank (empty or only contains whitespace).
+  bool? isBlank(dynamic value) {
+    return _isEmpty(value);
+  }
+
+  /// Checks if string is boolean.
+  bool isBool(String value) {
+    if (isNull(value)) {
+      return false;
+    }
 
-    // Will add new line if the sentence is bigger the 2 words.
+    return (value == 'true' || value == 'false');
+  }
+
+  Size get getTextSize {
+    final TextPainter textPainter = TextPainter(
+      text: TextSpan(text: this),
+      maxLines: 1,
+    )..layout(
+        minWidth: 0,
+        maxWidth: double.infinity,
+      );
+    return textPainter.size;
+  }
+
+  // Will add new line if the sentence is bigger the 2 words.
   /// [afterWords] will add new line after the selected word
   /// Example
   /// 'Hi, my name is'.wrapString(2)
-  /// 
+  ///
   /// will print:
   /// Hi, my
   /// name is
-  
+
   String wrapString(int afterWords) {
-    
     final wordsArr = this?.split(' ') ?? [];
 
     if (wordsArr.length > 2) {
@@ -54,7 +180,7 @@ extension StringExtensions on String? {
       male: '$this ${message?.male}', female: '$this ${message?.female}', other: '$this ${message?.other}');
 
   bool validateEmail() {
-    if(this == null) return false;
+    if (this == null) return false;
     return RegExp(r"^[a-zA-Z0-9.a-zA-Z0-9.!#$%&'*+-/=?^_`{|}~]+@[a-zA-Z0-9]+\.[a-zA-Z]+").hasMatch(this!);
   }
 
@@ -63,7 +189,7 @@ extension StringExtensions on String? {
 
   /// Return the string only if the delimiter exists in both ends, otherwise it will return the current string
   String? removeSurrounding(String delimiter) {
-    if(this == null) return null;
+    if (this == null) return null;
     final prefix = delimiter;
     final suffix = delimiter;
 
@@ -79,10 +205,12 @@ extension StringExtensions on String? {
   ///  Replace part of string after the first occurrence of given delimiter with the [replacement] string.
   ///  If the string does not contain the delimiter, returns [defaultValue] which defaults to the original string.
   String? replaceAfter(String delimiter, String replacement, [String? defaultValue]) {
-    if(this == null) return null;
+    if (this == null) return null;
     final index = this!.indexOf(delimiter);
     return (index == -1)
-        ? defaultValue.isEmptyOrNull ? this : defaultValue
+        ? defaultValue.isEmptyOrNull
+            ? this
+            : defaultValue
         : this!.replaceRange(index + 1, this!.length, replacement);
   }
 
@@ -90,14 +218,18 @@ extension StringExtensions on String? {
   /// Replace part of string before the first occurrence of given delimiter with the [replacement] string.
   ///  If the string does not contain the delimiter, returns [missingDelimiterValue?] which defaults to the original string.
   String? replaceBefore(String delimiter, String replacement, [String? defaultValue]) {
-    if(this == null) return null;
+    if (this == null) return null;
     final index = this!.indexOf(delimiter);
-    return (index == -1) ? defaultValue.isEmptyOrNull ? this : defaultValue : this!.replaceRange(0, index, replacement);
+    return (index == -1)
+        ? defaultValue.isEmptyOrNull
+            ? this
+            : defaultValue
+        : this!.replaceRange(0, index, replacement);
   }
 
   ///Returns `true` if at least one element matches the given [predicate].
   /// the [predicate] should have only one character
-  bool anyChar(bool predicate(String element)) => this.isEmptyOrNull ? false: this!.split('').any((s) => predicate(s));
+  bool anyChar(bool predicate(String element)) => this.isEmptyOrNull ? false : this!.split('').any((s) => predicate(s));
 
   /// Returns the string if it is not `null`, or the empty string otherwise
   String get orEmpty => this ?? "";
@@ -117,7 +249,7 @@ extension StringExtensions on String? {
   }
 
   /// Parses the string as an double or returns `null` if it is not a number.
-  double? toDoubleOrNull() => this == null ? null :double.tryParse(this!);
+  double? toDoubleOrNull() => this == null ? null : double.tryParse(this!);
 
   /// Parses the string as an int or returns `null` if it is not a number.
   int? toIntOrNull() => this == null ? null : int.tryParse(this!);
@@ -143,11 +275,9 @@ extension StringExtensions on String? {
 
   /// Shrink a string to be no more than [maxSize] in length, extending from the end.
   /// For example, in a string with 10 charachters, a [maxSize] of 3 would return the last 3 charachters.
-  String? limitFromEnd(int maxSize) => (this?.length ?? 0) < maxSize
-      ? this
-      : this!.substring(this!.length - maxSize);
+  String? limitFromEnd(int maxSize) => (this?.length ?? 0) < maxSize ? this : this!.substring(this!.length - maxSize);
 
-    /// Shrink a string to be no more than [maxSize] in length, extending from the start.
+  /// Shrink a string to be no more than [maxSize] in length, extending from the start.
   /// For example, in a string with 10 charachters, a [maxSize] of 3 would return the first 3 charachters.
   String? limitFromStart(int maxSize) => (this?.length ?? 0) < maxSize ? this : this!.substring(0, maxSize);
 
@@ -155,7 +285,7 @@ extension StringExtensions on String? {
   ///
   /// Returns `true` if this string is any of these values: `"true"`, `"yes"`, `"1"`, or if the string is a number and greater than 0, `false` if less than 1. This is also case insensitive.
   bool get asBool {
-    var s = this?.trim().toLowerCase()??"false";
+    var s = this?.trim().toLowerCase() ?? "false";
     num n;
     try {
       n = num.parse(s);
diff --git a/pubspec.yaml b/pubspec.yaml
index afe733f..12f7ae7 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: dart_extensions
 description: Set of method-extensions for dart that makes using framework in a much easier and clean way also adds additional functionality.
-version: 2.0.4
+version: 2.0.5
 documentation: https://github.com/droididan/dart_extentions
 homepage: https://github.com/droididan/dart_extentions
 

From abe82fe7b3f1f1352331ed9113536a942622aa04 Mon Sep 17 00:00:00 2001
From: Vincenzo Sarnataro <>
Date: Fri, 26 Mar 2021 15:39:56 +0100
Subject: [PATCH 09/11] add extensions for nullable Iterable add orEmpty
 extensions

---
 lib/src/iterable.dart | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/lib/src/iterable.dart b/lib/src/iterable.dart
index 249b10b..7c69efb 100644
--- a/lib/src/iterable.dart
+++ b/lib/src/iterable.dart
@@ -18,14 +18,13 @@ import 'package:quiver/iterables.dart';
 import 'data_stractures/stack.dart';
 import 'equality.dart';
 
-typedef IndexedPredicate<T> = bool Function(int index, T);
+extension CollectionsNullableExtension<T> on Iterable<T>? {
 
-extension CollectionsExtensions<T> on Iterable<T> {
-  /// Returns this Iterable if it's not `null` and the empty list otherwise.
-  Iterable<T> orEmpty() => this;
+ /// Returns this Iterable if it's not `null` and the empty list otherwise.
+  Iterable<T> orEmpty() => this ?? Iterable<T>.empty();
 
   ///Returns `true` if this nullable iterable is either null or empty.
-  bool get isEmptyOrNull => this.isEmpty;
+  bool get isEmptyOrNull => this?.isEmpty ?? true;
 
   /// Returns `true` if at least one element matches the given [predicate].
   bool any(bool predicate(T element)) {
@@ -52,14 +51,20 @@ extension CollectionsExtensions<T> on Iterable<T> {
   /// the combination of them two.
   zip<T>(Iterable<T> iterable) sync* {
     if (iterable.isEmptyOrNull) return;
-    final iterables = List<Iterable>.empty()..add(this.orEmpty())..add(iterable);
+    final iterables = List<Iterable>.empty()
+      ..add(this.orEmpty())
+      ..add(iterable);
 
     final iterators = iterables.map((e) => e.iterator).toList(growable: false);
     while (iterators.every((e) => e.moveNext())) {
       yield iterators.map((e) => e.current).toList(growable: false);
     }
   }
+}
 
+typedef IndexedPredicate<T> = bool Function(int index, T);
+
+extension CollectionsExtensions<T> on Iterable<T> {
   ///Sorts elements in the array in-place according to natural sort order of the value returned by specified [selector] function.
   Iterable<T> sortBy<TKey>(
     TKey Function(T) keySelector, {

From 8cd7d19bf96eb71b09971665be88b08cc67ea566 Mon Sep 17 00:00:00 2001
From: Vincenzo Sarnataro <>
Date: Fri, 26 Mar 2021 15:40:07 +0100
Subject: [PATCH 10/11] add new test

---
 test/iterable_tests.dart | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/test/iterable_tests.dart b/test/iterable_tests.dart
index cdac2ca..18616cd 100644
--- a/test/iterable_tests.dart
+++ b/test/iterable_tests.dart
@@ -201,6 +201,26 @@ main() {
     expect(["a", "b", "a"].toMutableSet(), ["a", "b"]);
   });
 
+    test('intersect', () {
+      expect(Set.from([1, 2, 3, 4]).intersect(Set.from([3, 4, 5, 6])), [1, 2, 3, 4, 5, 6]);
+      expect(Set.from([-1, -2, -3, 4]).intersect(Set.from([3, 4, 5, 6])), [-1, -2, -3, 4, 3, 5, 6]);
+    });
+
+    test('orEmpty',(){
+      List<int>? list;
+      expect(list.orEmpty(), List<int>.empty());
+      list= [1,2,3];
+      expect(list.orEmpty(), [1,2,3]);
+    });
+
+    test('isEmptyOrNull',(){
+      List<int>? list;
+      expect(list.isEmptyOrNull, true);
+      list= [];
+      expect(list.isEmptyOrNull, true);
+      list= [1,2,3];
+      expect(list.isEmptyOrNull, false);
+    });
   test('intersect', () {
     expect(Set.from([1, 2, 3, 4]).intersect(Set.from([3, 4, 5, 6])), [1, 2, 3, 4, 5, 6]);
     expect(Set.from([-1, -2, -3, 4]).intersect(Set.from([3, 4, 5, 6])), [-1, -2, -3, 4, 3, 5, 6]);

From d9c2443f1a219ff913f67688b9b14f53329b34ff Mon Sep 17 00:00:00 2001
From: Vincenzo Sarnatarp <sarnataro.vincenzo@gmail.com>
Date: Mon, 31 May 2021 22:20:41 +0200
Subject: [PATCH 11/11] fix test in iterable_tests.dart

---
 lib/src/iterable.dart    |  6 +++---
 lib/src/model/user.dart  | 13 +++++++++++++
 test/iterable_tests.dart |  7 +++++--
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/lib/src/iterable.dart b/lib/src/iterable.dart
index 7c69efb..fba5aca 100644
--- a/lib/src/iterable.dart
+++ b/lib/src/iterable.dart
@@ -51,7 +51,7 @@ extension CollectionsNullableExtension<T> on Iterable<T>? {
   /// the combination of them two.
   zip<T>(Iterable<T> iterable) sync* {
     if (iterable.isEmptyOrNull) return;
-    final iterables = List<Iterable>.empty()
+    final iterables = List<Iterable>.empty(growable: true)
       ..add(this.orEmpty())
       ..add(iterable);
 
@@ -128,7 +128,7 @@ extension CollectionsExtensions<T> on Iterable<T> {
   List<T> takeOnly(int n) {
     if (n == 0) return [];
 
-    var list = List<T>.empty();
+    var list = List<T>.empty(growable: true);
     var thisList = this.toList();
     if (this is Iterable) {
       final resultSize = this.length - n;
@@ -146,7 +146,7 @@ extension CollectionsExtensions<T> on Iterable<T> {
   List<T> drop(int n) {
     if (n == 0) return [];
 
-    var list = List<T>.empty();
+    var list = List<T>.empty(growable: true);
     var originalList = this.toList();
     if (this is Iterable) {
       final resultSize = this.length - n;
diff --git a/lib/src/model/user.dart b/lib/src/model/user.dart
index 57be87f..5df6f80 100644
--- a/lib/src/model/user.dart
+++ b/lib/src/model/user.dart
@@ -17,6 +17,19 @@ class User {
 
   User(this.age,this.name);
 
+
+  @override
+  bool operator ==(other) {
+    return (other is User)
+        && other.name == name
+        && other.age == age;
+  }
+
+
+  @override
+  int get hashCode => age.hashCode ^ name.hashCode;
+
+
   @override
   String toString() {
     return "$age, $name";
diff --git a/test/iterable_tests.dart b/test/iterable_tests.dart
index 18616cd..b6422ea 100644
--- a/test/iterable_tests.dart
+++ b/test/iterable_tests.dart
@@ -19,7 +19,7 @@ main() {
 
   test('result of whereIndex', () {
     final result = users.whereIndexed((index, _) => index == 2);
-    expect(result, [User(22, "Oded")]);
+    expect(result.toList(), [User(22, "Oded")]);
   });
 
   test('if all elements match the predicate', () {
@@ -41,7 +41,10 @@ main() {
 
   test("first or null", () {
     final list = [1, 45, 6, 9];
-    expect(null, list.firstWhere((element) => element == 7));
+    expect(1, list.firstOrNull);
+    final list2 =List.empty();
+    expect(null, list2.firstOrNull);
+
   });
 
   test('filter', () {