From 1da0554b17d74e124770f140db1081f4bcb4053d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kasper=20Overg=C3=A5rd=20Nielsen?= <kasper@byolimit.com>
Date: Mon, 8 May 2023 11:25:34 +0200
Subject: [PATCH] Override first, last and single on RealmResults

Avoid instantiating a _RealmResultsIterator for first and
single calls, and avoid iterating the entire collection for last.
---
 lib/src/results.dart | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/lib/src/results.dart b/lib/src/results.dart
index a90a440fe4..210a6d9d27 100644
--- a/lib/src/results.dart
+++ b/lib/src/results.dart
@@ -16,7 +16,6 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 import 'dart:async';
-import 'dart:collection' as collection;
 import 'dart:ffi';
 
 import 'collections.dart';
@@ -28,7 +27,7 @@ import 'realm_object.dart';
 /// added to or deleted from the Realm that match the underlying query.
 ///
 /// {@category Realm}
-class RealmResults<T extends Object?> extends collection.IterableBase<T> with RealmEntity implements Finalizable {
+class RealmResults<T extends Object?> extends Iterable<T> with RealmEntity implements Finalizable {
   final RealmObjectMetadata? _metadata;
   final RealmResultsHandle _handle;
 
@@ -56,11 +55,9 @@ class RealmResults<T extends Object?> extends collection.IterableBase<T> with Re
     }
   }
 
-  /// `true` if the `Results` collection is empty.
   @override
   bool get isEmpty => length == 0;
 
-  /// Returns a new `Iterator` that allows iterating the elements in this `RealmResults`.
   @override
   Iterator<T> get iterator {
     var results = this;
@@ -71,10 +68,23 @@ class RealmResults<T extends Object?> extends collection.IterableBase<T> with Re
     return _RealmResultsIterator(results);
   }
 
-  /// The number of values in this `Results` collection.
   @override
   int get length => realmCore.getResultsCount(this);
 
+  @override
+  T get first => this[0];
+
+  @override
+  T get last => this[length - 1];
+
+  @override
+  T get single {
+    if (length != 1) {
+      throw StateError('Expected exactly one element but was $length');
+    }
+    return this[0];
+  }
+
   /// Creates a frozen snapshot of this query.
   RealmResults<T> freeze() {
     if (isFrozen) {