diff --git a/lib/src/core/paging_state.dart b/lib/src/core/paging_state.dart
index 7889005..721352b 100644
--- a/lib/src/core/paging_state.dart
+++ b/lib/src/core/paging_state.dart
@@ -42,15 +42,15 @@ abstract class PagingState<PageKeyType extends Object,
   /// If a field is not provided, it will default to the current value.
   ///
   /// While this implementation technically accepts Futures, passing a Future is invalid.
-  /// The FutureOr type is used to allow for the Omit sentinel value,
+  /// The Defaulted type is used to allow for the Omit sentinel value,
   /// which is required to distinguish between a parameter being omitted and a parameter being set to null.
   // copyWith a la Remi Rousselet: https://github.com/dart-lang/language/issues/137#issuecomment-583783054
   PagingState<PageKeyType, ItemType> copyWith({
-    FutureOr<List<List<ItemType>>?>? pages = const Omit(),
-    FutureOr<List<PageKeyType>?>? keys = const Omit(),
-    FutureOr<Object?>? error = const Omit(),
-    FutureOr<bool>? hasNextPage = const Omit(),
-    FutureOr<bool>? isLoading = const Omit(),
+    Defaulted<List<List<ItemType>>?>? pages = const Omit(),
+    Defaulted<List<PageKeyType>?>? keys = const Omit(),
+    Defaulted<Object?>? error = const Omit(),
+    Defaulted<bool>? hasNextPage = const Omit(),
+    Defaulted<bool>? isLoading = const Omit(),
   });
 
   /// Returns a copy this [PagingState] but
@@ -70,6 +70,8 @@ extension ItemListExtension<PageKeyType extends Object, ItemType extends Object>
   List<ItemType>? get items => pages?.expand((e) => e).toList();
 }
 
+typedef Defaulted<T> = FutureOr<T>;
+
 /// Sentinel value to omit a parameter from a copyWith call.
 /// This is used to distinguish between a parameter being omitted and a parameter
 /// being set to null.
diff --git a/lib/src/core/paging_state_base.dart b/lib/src/core/paging_state_base.dart
index a2ce48a..ad16ec6 100644
--- a/lib/src/core/paging_state_base.dart
+++ b/lib/src/core/paging_state_base.dart
@@ -1,5 +1,3 @@
-import 'dart:async';
-
 import 'package:collection/collection.dart';
 import 'package:flutter/foundation.dart';
 import 'package:infinite_scroll_pagination/src/core/paging_state.dart';
@@ -10,34 +8,23 @@ import 'package:infinite_scroll_pagination/src/core/paging_state.dart';
 /// all of its fields are deeply equal.
 base class PagingStateBase<PageKeyType extends Object, ItemType extends Object>
     implements PagingState<PageKeyType, ItemType> {
-  factory PagingStateBase({
+  /// Creates a [PagingStateBase] with the given parameters.
+  ///
+  /// Ensures that [pages] and [keys] are unmodifiable lists.
+  PagingStateBase({
     List<List<ItemType>>? pages,
     List<PageKeyType>? keys,
-    Object? error,
-    bool hasNextPage = true,
-    bool isLoading = false,
-  }) =>
-      PagingStateBase._(
-        pages: switch (pages) {
+    this.error,
+    this.hasNextPage = true,
+    this.isLoading = false,
+  })  : pages = switch (pages) {
           null => null,
           _ => List.unmodifiable(pages),
         },
-        keys: switch (keys) {
+        keys = switch (keys) {
           null => null,
           _ => List.unmodifiable(keys),
-        },
-        error: error,
-        hasNextPage: hasNextPage,
-        isLoading: isLoading,
-      );
-
-  const PagingStateBase._({
-    required this.pages,
-    required this.keys,
-    required this.error,
-    required this.hasNextPage,
-    required this.isLoading,
-  });
+        };
 
   @override
   final List<List<ItemType>>? pages;
@@ -56,11 +43,11 @@ base class PagingStateBase<PageKeyType extends Object, ItemType extends Object>
 
   @override
   PagingState<PageKeyType, ItemType> copyWith({
-    FutureOr<List<List<ItemType>>?>? pages = const Omit(),
-    FutureOr<List<PageKeyType>?>? keys = const Omit(),
-    FutureOr<Object?>? error = const Omit(),
-    FutureOr<bool>? hasNextPage = const Omit(),
-    FutureOr<bool>? isLoading = const Omit(),
+    Defaulted<List<List<ItemType>>?>? pages = const Omit(),
+    Defaulted<List<PageKeyType>?>? keys = const Omit(),
+    Defaulted<Object?>? error = const Omit(),
+    Defaulted<bool>? hasNextPage = const Omit(),
+    Defaulted<bool>? isLoading = const Omit(),
   }) =>
       PagingStateBase(
         pages: pages is Omit ? this.pages : pages as List<List<ItemType>>?,