Remove IterableExtensions that have exact equivalents in the SDK

Since Dart 3.0, these extensions are in the SDK, exported from core: firstOrNull, lastOrNull, singleOrNull, elementAtOrNull This package already bumped the version to be above that. So, the deletion will not cause any breakage to users, only potential "unused import" warnings.
dart-archive · Jan 25, 2024 · d85ae60 · d85ae60
1 parent 2d57a82
commit d85ae60
Show file tree

Hide file tree

Showing 4 changed files with 3 additions and 112 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,6 +4,9 @@
 - Shuffle `IterableExtension.sample` results.
 - Fix `mergeSort` when the runtime iterable generic is a subtype of the static
   generic.
+- Remove `firstOrNull`, `lastOrNull`, `singleOrNull` and `elementAtOrNull()`
+  from `IterableExtensions`. Since Dart 3.0, exact equivalents to these are
+  available in Dart core, so 'package:collection' would only be shadowing these.
 - Require Dart `^3.1.0`
 - Mark "mixin" classes as `mixin`.
 

diff --git a/lib/src/iterable_extensions.dart b/lib/src/iterable_extensions.dart
@@ -269,13 +269,6 @@ extension IterableExtension<T> on Iterable<T> {
     return null;
   }
 
-  /// The first element, or `null` if the iterable is empty.
-  T? get firstOrNull {
-    var iterator = this.iterator;
-    if (iterator.moveNext()) return iterator.current;
-    return null;
-  }
-
   /// The last element satisfying [test], or `null` if there are none.
   T? lastWhereOrNull(bool Function(T element) test) {
     T? result;
@@ -297,12 +290,6 @@ extension IterableExtension<T> on Iterable<T> {
     return result;
   }
 
-  /// The last element, or `null` if the iterable is empty.
-  T? get lastOrNull {
-    if (isEmpty) return null;
-    return last;
-  }
-
   /// The single element satisfying [test].
   ///
   /// Returns `null` if there are either no elements
@@ -348,32 +335,6 @@ extension IterableExtension<T> on Iterable<T> {
     return result;
   }
 
-  /// The single element of the iterable, or `null`.
-  ///
-  /// The value is `null` if the iterable is empty
-  /// or it contains more than one element.
-  T? get singleOrNull {
-    var iterator = this.iterator;
-    if (iterator.moveNext()) {
-      var result = iterator.current;
-      if (!iterator.moveNext()) {
-        return result;
-      }
-    }
-    return null;
-  }
-
-  /// The [index]th element, or `null` if there is no such element.
-  ///
-  /// Returns the element at position [index] of this iterable,
-  /// just like [elementAt], if this iterable has such an element.
-  /// If this iterable does not have enough elements to have one with the given
-  /// [index], the `null` value is returned, unlike [elementAt] which throws
-  /// instead.
-  ///
-  /// The [index] must not be negative.
-  T? elementAtOrNull(int index) => skip(index).firstOrNull;
-
   /// Associates the elements in `this` by the value returned by [key].
   ///
   /// Returns a map from keys computed by [key] to the last value for which

diff --git a/lib/src/list_extensions.dart b/lib/src/list_extensions.dart
@@ -259,17 +259,6 @@ extension ListExtensions<E> on List<E> {
     return true;
   }
 
-  /// The [index]th element, or `null` if there is no such element.
-  ///
-  /// Returns the element at position [index] of this list,
-  /// just like [elementAt], if this list has such an element.
-  /// If this list does not have enough elements to have one with the given
-  /// [index], the `null` value is returned, unlike [elementAt] which throws
-  /// instead.
-  ///
-  /// The [index] must not be negative.
-  E? elementAtOrNull(int index) => (index < length) ? this[index] : null;
-
   /// Contiguous [slice]s of `this` with the given [length].
   ///
   /// Each slice is a view of this list [length] elements long, except for the

diff --git a/test/extensions_test.dart b/test/extensions_test.dart
@@ -426,17 +426,6 @@ void main() {
               0);
         });
       });
-      group('.firstOrNull', () {
-        test('empty', () {
-          expect(iterable([]).firstOrNull, null);
-        });
-        test('single', () {
-          expect(iterable([1]).firstOrNull, 1);
-        });
-        test('first of multiple', () {
-          expect(iterable([1, 3, 5]).firstOrNull, 1);
-        });
-      });
       group('.lastWhereOrNull', () {
         test('empty', () {
           expect(iterable([]).lastWhereOrNull(unreachable), null);
@@ -474,17 +463,6 @@ void main() {
               7);
         });
       });
-      group('.lastOrNull', () {
-        test('empty', () {
-          expect(iterable([]).lastOrNull, null);
-        });
-        test('single', () {
-          expect(iterable([1]).lastOrNull, 1);
-        });
-        test('last of multiple', () {
-          expect(iterable([1, 3, 5]).lastOrNull, 5);
-        });
-      });
       group('.singleWhereOrNull', () {
         test('empty', () {
           expect(iterable([]).singleWhereOrNull(unreachable), null);
@@ -526,17 +504,6 @@ void main() {
               null);
         });
       });
-      group('.singleOrNull', () {
-        test('empty', () {
-          expect(iterable([]).singleOrNull, null);
-        });
-        test('single', () {
-          expect(iterable([1]).singleOrNull, 1);
-        });
-        test('multiple', () {
-          expect(iterable([1, 3, 5]).singleOrNull, null);
-        });
-      });
       group('.lastBy', () {
         test('empty', () {
           expect(iterable([]).lastBy((dynamic _) {}), {});
@@ -1204,21 +1171,6 @@ void main() {
         });
       });
     });
-    group('.elementAtOrNull', () {
-      test('empty', () async {
-        expect(iterable([]).elementAtOrNull(0), isNull);
-      });
-      test('negative index', () async {
-        expect(() => iterable([1]).elementAtOrNull(-1),
-            throwsA(isA<RangeError>()));
-      });
-      test('index within range', () async {
-        expect(iterable([1]).elementAtOrNull(0), 1);
-      });
-      test('index too high', () async {
-        expect(iterable([1]).elementAtOrNull(1), isNull);
-      });
-    });
     group('.slices', () {
       test('empty', () {
         expect(iterable(<int>[]).slices(1), []);
@@ -1820,20 +1772,6 @@ void main() {
               ['1', 'b']);
         });
       });
-      group('.elementAtOrNull', () {
-        test('empty', () async {
-          expect([].elementAtOrNull(0), isNull);
-        });
-        test('negative index', () async {
-          expect(() => [1].elementAtOrNull(-1), throwsA(isA<RangeError>()));
-        });
-        test('index within range', () async {
-          expect([1].elementAtOrNull(0), 1);
-        });
-        test('index too high', () async {
-          expect([1].elementAtOrNull(1), isNull);
-        });
-      });
       group('.slices', () {
         test('empty', () {
           expect(<int>[].slices(1), []);