From c7e7643fe56cb26fae47dba843632241cf3394da Mon Sep 17 00:00:00 2001
From: julian <julian@cypherstack.com>
Date: Thu, 30 May 2024 12:46:41 -0600
Subject: [PATCH] chunked list extension

---
 lib/utilities/extensions/impl/list.dart  | 19 ++++++++++++++
 test/utilities/extensions/list_test.dart | 33 ++++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 lib/utilities/extensions/impl/list.dart
 create mode 100644 test/utilities/extensions/list_test.dart

diff --git a/lib/utilities/extensions/impl/list.dart b/lib/utilities/extensions/impl/list.dart
new file mode 100644
index 000000000..c802f2704
--- /dev/null
+++ b/lib/utilities/extensions/impl/list.dart
@@ -0,0 +1,19 @@
+extension ListExt<T> on List<T> {
+  List<List<T>> chunked({required int chunkSize}) {
+    final remainder = length % chunkSize;
+    final count = length ~/ chunkSize;
+    final List<List<T>> result = [];
+
+    int i = 0;
+    while (i < count) {
+      result.add(sublist(i, i + chunkSize));
+      i++;
+    }
+
+    if (remainder > 0) {
+      result.add(sublist(i, i + remainder));
+    }
+
+    return result;
+  }
+}
diff --git a/test/utilities/extensions/list_test.dart b/test/utilities/extensions/list_test.dart
new file mode 100644
index 000000000..594328034
--- /dev/null
+++ b/test/utilities/extensions/list_test.dart
@@ -0,0 +1,33 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:stackwallet/utilities/extensions/extensions.dart';
+
+void main() {
+  test("Empty list", () {
+    final List<int> list = [];
+    expect(
+      list.chunked(chunkSize: 3).isEmpty,
+      true,
+    );
+  });
+
+  test("No remainder", () {
+    final List<int> list = [0, 1, 2, 3, 4, 5, 6, 7, 8];
+    final chunked = list.chunked(chunkSize: 3);
+    expect(chunked.length == 3, true);
+    expect(
+      chunked.map((e) => e.length == 3).reduce((v, e) => v && e),
+      true,
+    );
+  });
+
+  test("Some remainder", () {
+    final List<int> list = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+    final chunked = list.chunked(chunkSize: 3);
+    expect(chunked.length == 4, true);
+    expect(chunked.last.length == 1, true);
+    expect(
+      chunked.map((e) => e.length == 3).reduce((v, e) => v && e),
+      false,
+    );
+  });
+}