fix: Add min and max to DateTime.

mathrunet · Nov 17, 2023 · bc76dcd · bc76dcd
1 parent 8eeffd0
commit bc76dcd
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Showing 4 changed files with 46 additions and 0 deletions.
diff --git a/packages/katana/lib/extension/date_time_iterable_extensions.dart b/packages/katana/lib/extension/date_time_iterable_extensions.dart
@@ -40,4 +40,22 @@ extension DateTimeIterableExtensions on Iterable<DateTime> {
     }
     return res;
   }
+
+  /// Calculates the most recent date in the [DateTime] list.
+  ///
+  /// [DateTime]のリストの中で一番新しい日付を算出します。
+  DateTime max() {
+    return DateTime.fromMicrosecondsSinceEpoch(
+      map((e) => e.microsecondsSinceEpoch).reduce((a, b) => a > b ? a : b),
+    );
+  }
+
+  /// Calculates the oldest date in the [DateTime] list.
+  ///
+  /// [DateTime]のリストの中で一番古い日付を算出します。
+  DateTime min() {
+    return DateTime.fromMicrosecondsSinceEpoch(
+      map((e) => e.microsecondsSinceEpoch).reduce((a, b) => a < b ? a : b),
+    );
+  }
 }
diff --git a/packages/katana/test/date_time_iterable_extensions_test.dart b/packages/katana/test/date_time_iterable_extensions_test.dart
@@ -26,4 +26,24 @@ void main() {
       DateTime(2023, 3, 23, 10, 32, 10),
     );
   });
+  test("DateTimeIterableExtensions.min", () {
+    final minDateTime = DateTime(2022, 12, 23, 10, 32, 10);
+    final maxDateTime = DateTime(2023, 12, 23, 10, 32, 10);
+    final dateTimes = [
+      ...List.generate(10, (i) => minDateTime.add(Duration(days: i * 10))),
+      maxDateTime,
+    ];
+    expect(dateTimes.min().millisecondsSinceEpoch,
+        minDateTime.millisecondsSinceEpoch);
+  });
+  test("DateTimeIterableExtensions.max", () {
+    final minDateTime = DateTime(2022, 12, 23, 10, 32, 10);
+    final maxDateTime = DateTime(2023, 12, 23, 10, 32, 10);
+    final dateTimes = [
+      ...List.generate(10, (i) => minDateTime.add(Duration(days: i * 10))),
+      maxDateTime,
+    ];
+    expect(dateTimes.max().millisecondsSinceEpoch,
+        maxDateTime.millisecondsSinceEpoch);
+  });
 }
diff --git a/packages/katana/test/double_iterable_extensions_test.dart b/packages/katana/test/double_iterable_extensions_test.dart
@@ -15,6 +15,10 @@ void main() {
     expect(doubles.nearestOrNull(5000), 100.0);
     expect(doubles.nearestOrNull(double.nan), null);
   });
+  test("DoubleIterableExtensions.sum", () {
+    final doubles = [1.0, 2.0, 3.0, 4.0];
+    expect(doubles.sum(), 10.0);
+  });
   test("DoubleIterableExtensions.average", () {
     final doubles = [1.0, 2.0, 3.0, 4.0];
     expect(doubles.average(), 2.5);

diff --git a/packages/katana/test/int_iterable_extensions_test.dart b/packages/katana/test/int_iterable_extensions_test.dart
@@ -15,6 +15,10 @@ void main() {
     expect(ints.nearestOrNull(5000), 100);
     expect(<int>[].nearestOrNull(5000), null);
   });
+  test("IntIterableExtensions.sum", () {
+    final ints = [1, 2, 3, 4];
+    expect(ints.sum(), 10);
+  });
   test("IntIterableExtensions.average", () {
     final ints = [1, 2, 3, 4];
     expect(ints.average(), 2.5);