From 5914d63888d80d6d93e0ba44d35d6b14346d8341 Mon Sep 17 00:00:00 2001
From: Yehuda Ringler <yrappdev@gmail.com>
Date: Mon, 12 Apr 2021 22:28:05 -0400
Subject: [PATCH] optional comparer, export equality

---
 lib/dart_extensions.dart | 2 +-
 lib/src/iterable.dart    | 9 ++++-----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/lib/dart_extensions.dart b/lib/dart_extensions.dart
index 550c59b..eeff59d 100644
--- a/lib/dart_extensions.dart
+++ b/lib/dart_extensions.dart
@@ -24,6 +24,7 @@ export 'package:dart_extensions/src/flutter/container.dart';
 export 'package:dart_extensions/src/flutter/gesture_detector.dart';
 export 'package:dart_extensions/src/flutter/navigation.dart';
 export 'package:dart_extensions/src/flutter/padding.dart';
+export 'package:dart_extensions/src/equality.dart';
 export 'package:dart_extensions/src/http.dart';
 export 'package:dart_extensions/src/int.dart';
 export 'package:dart_extensions/src/iterable.dart';
@@ -32,4 +33,3 @@ 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/flutter/widgets.dart';
- 
diff --git a/lib/src/iterable.dart b/lib/src/iterable.dart
index 364bd1a..52bf704 100644
--- a/lib/src/iterable.dart
+++ b/lib/src/iterable.dart
@@ -19,14 +19,13 @@ 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, {
-    required EqualityComparer<TKey> keyComparer,
+    EqualityComparer<TKey>? keyComparer,
   }) {
-    return InternalOrderedIterable(this, keySelector, keyComparer, false);
+    return InternalOrderedIterable(
+        this, keySelector, keyComparer ?? EqualityComparer<TKey>(), false);
   }
 
   /// Returns `true` if at least one element matches the given [predicate].
@@ -124,7 +123,7 @@ 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();