Add removeLastOrNull()

passsy · Oct 31, 2021 · f173b94 · f173b94
1 parent 1eb8c03
commit f173b94
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Showing 3 changed files with 111 additions and 77 deletions.
diff --git a/lib/src/collection/kt_list_mutable.dart b/lib/src/collection/kt_list_mutable.dart
@@ -168,6 +168,15 @@ extension KtMutableListExtensions<T> on KtMutableList<T> {
     }
     return removeAt(lastIndex);
   }
+
+  /// Removes the last element from this mutable list.
+  ///
+  /// Returns that removed element, or throws [NoSuchElementException] if this list is empty.
+  T? removeLastOrNull() {
+    if (isEmpty()) return null;
+    return removeAt(lastIndex);
+  }
+
   /// Reverses elements in the list in-place.
   void reverse() {
     final mid = size >> 1;

diff --git a/test/collection/list_mutable_extensions_test.dart b/test/collection/list_mutable_extensions_test.dart
@@ -90,6 +90,108 @@ void testList(
     });
   });
 
+  group("removeFirst", () {
+    test("remove first item when found", () {
+      final list = mutableListOf("1", "2", "3");
+      final result = list.removeFirst();
+      expect(list, mutableListOf("2", "3"));
+      expect(result, "1");
+    });
+    test("remove first item when length is 1", () {
+      final list = mutableListOf("1");
+      final result = list.removeFirst();
+      expect(list, mutableListOf());
+      expect(result, "1");
+    });
+    test("remove first item when null", () {
+      final list = mutableListOf(null, null);
+      final result = list.removeFirst();
+      expect(list, mutableListOf(null));
+      expect(result, null);
+    });
+    test("throw when list is empty", () {
+      final list = mutableListOf();
+      expect(() => list.removeFirst(), throwsA(isA<NoSuchElementException>()));
+    });
+  });
+
+  group("removeFirstOrNull", () {
+    test("remove first item when found", () {
+      final list = mutableListOf("1", "2", "3");
+      final result = list.removeFirstOrNull();
+      expect(list, mutableListOf("2", "3"));
+      expect(result, "1");
+    });
+    test("remove first item when length is 1", () {
+      final list = mutableListOf("1");
+      final result = list.removeFirstOrNull();
+      expect(list, mutableListOf());
+      expect(result, "1");
+    });
+    test("null when item in list is null", () {
+      final list = mutableListOf(null, null);
+      final result = list.removeFirstOrNull();
+      expect(list, mutableListOf(null));
+      expect(result, null);
+    });
+    test("null when list is empty", () {
+      final list = mutableListOf();
+      final result = list.removeFirstOrNull();
+      expect(list, mutableListOf());
+      expect(result, null);
+    });
+  });
+
+  group("removeLast", () {
+    test("remove last item when found", () {
+      final list = mutableListOf("1", "2", "3");
+      final result = list.removeLast();
+      expect(list, mutableListOf("1", "2"));
+      expect(result, "3");
+    });
+    test("remove last item when length is 1", () {
+      final list = mutableListOf("1");
+      final result = list.removeLast();
+      expect(list, mutableListOf());
+      expect(result, "1");
+    });
+    test("remove last item when null", () {
+      final list = mutableListOf(null, "2", null);
+      final result = list.removeLast();
+      expect(list, mutableListOf(null, "2"));
+      expect(result, null);
+    });
+    test("throw when list is empty", () {
+      final list = mutableListOf();
+      expect(() => list.removeLast(), throwsA(isA<NoSuchElementException>()));
+    });
+  });
+
+  group("removeLastOrNull", () {
+    test("remove last item when found", () {
+      final list = mutableListOf("1", "2", "3");
+      final result = list.removeLastOrNull();
+      expect(list, mutableListOf("1", "2"));
+      expect(result, "3");
+    });
+    test("remove last item when length is 1", () {
+      final list = mutableListOf("1");
+      final result = list.removeLastOrNull();
+      expect(list, mutableListOf());
+      expect(result, "1");
+    });
+    test("remove last item when null", () {
+      final list = mutableListOf(null, "2", null);
+      final result = list.removeLastOrNull();
+      expect(list, mutableListOf(null, "2"));
+      expect(result, null);
+    });
+    test("null when list is empty", () {
+      final list = mutableListOf();
+      expect(list.removeLastOrNull(), null);
+    });
+  });
+
   group("sorted", () {
     String lastChar(String it) {
       final last = it.runes.last;

diff --git a/test/collection/list_mutable_test.dart b/test/collection/list_mutable_test.dart
@@ -210,81 +210,4 @@ void testList(
       expect(linkedSetOf<num>(1, 2, 3), linkedSetOf<int>(1, 2, 3));
     });
   });
-
-  group("removeFirst", () {
-    test("remove first item when found", () {
-      final list = mutableListOf("1", "2", "3");
-      final result = list.removeFirst();
-      expect(list, mutableListOf("2", "3"));
-      expect(result, "1");
-    });
-    test("remove first item when length is 1", () {
-      final list = mutableListOf("1");
-      final result = list.removeFirst();
-      expect(list, mutableListOf());
-      expect(result, "1");
-    });
-    test("remove first item when null", () {
-      final list = mutableListOf(null, null);
-      final result = list.removeFirst();
-      expect(list, mutableListOf(null));
-      expect(result, null);
-    });
-    test("throw when list is empty", () {
-      final list = mutableListOf();
-      expect(() => list.removeFirst(), throwsA(isA<NoSuchElementException>()));
-    });
-  });
-
-  group("removeLast", () {
-    test("remove last item when found", () {
-      final list = mutableListOf("1", "2", "3");
-      final result = list.removeLast();
-      expect(list, mutableListOf("1", "2"));
-      expect(result, "3");
-    });
-    test("remove last item when length is 1", () {
-      final list = mutableListOf("1");
-      final result = list.removeLast();
-      expect(list, mutableListOf());
-      expect(result, "1");
-    });
-    test("remove last item when null", () {
-      final list = mutableListOf(null, "2", null);
-      final result = list.removeLast();
-      expect(list, mutableListOf(null, "2"));
-      expect(result, null);
-    });
-    test("throw when list is empty", () {
-      final list = mutableListOf();
-      expect(() => list.removeLast(), throwsA(isA<NoSuchElementException>()));
-    });
-  });
-
-  group("removeFirstOrNull", () {
-    test("remove first item when found", () {
-      final list = mutableListOf("1", "2", "3");
-      final result = list.removeFirstOrNull();
-      expect(list, mutableListOf("2", "3"));
-      expect(result, "1");
-    });
-    test("remove first item when length is 1", () {
-      final list = mutableListOf("1");
-      final result = list.removeFirstOrNull();
-      expect(list, mutableListOf());
-      expect(result, "1");
-    });
-    test("null when item in list is null", () {
-      final list = mutableListOf(null, null);
-      final result = list.removeFirstOrNull();
-      expect(list, mutableListOf(null));
-      expect(result, null);
-    });
-    test("null when list is empty", () {
-      final list = mutableListOf();
-      final result = list.removeFirstOrNull();
-      expect(list, mutableListOf());
-      expect(result, null);
-    });
-  });
 }