From 931a288b0e12fa547d0d8ccc4bad6b3a01704a27 Mon Sep 17 00:00:00 2001
From: otto-dev <ignatius.public@gmail.com>
Date: Sat, 16 Apr 2022 08:07:03 +1000
Subject: [PATCH 1/3] Add catchAsync + tests

---
 lib/src/either.dart   |  8 ++++++++
 test/either_test.dart | 16 ++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/lib/src/either.dart b/lib/src/either.dart
index 2ee5b58..ee8dbd2 100644
--- a/lib/src/either.dart
+++ b/lib/src/either.dart
@@ -213,6 +213,14 @@ Either<dynamic, A> catching<A>(Function0<A> thunk) {
   }
 }
 
+Future<Either<dynamic, A>> catchAsync<A>(Function0<Future<A>> f) async {
+  try {
+    return Right(await f());
+  } catch (e) {
+    return Left(e);
+  }
+}
+
 class EitherMonad<L> extends MonadOpsMonad<Either<L, dynamic>> {
   EitherMonad(): super(right);
 }
diff --git a/test/either_test.dart b/test/either_test.dart
index 6461710..e2c66c5 100644
--- a/test/either_test.dart
+++ b/test/either_test.dart
@@ -103,4 +103,20 @@ void main() {
       expect(right.value, 2);
     });
   });
+
+  group("catchAsync", () {
+    test("successful future", () async {
+      expect(await catchAsync(() => Future.value(2)), right(2));
+    });
+
+    test("failed future", () async {
+      final error = Exception("foobar");
+      expect(await catchAsync(() => Future.error(error)), left(error));
+    });
+
+    test("throwing synchronous function body", () async {
+      final error = Exception("foobar");
+      expect(await catchAsync(() => throw error), left(error));
+    });
+  });
 }

From bf4fb166b9783ad72cb35cf25002eafbc4b32631 Mon Sep 17 00:00:00 2001
From: otto-dev <ignatius.public@gmail.com>
Date: Sat, 16 Apr 2022 08:12:42 +1000
Subject: [PATCH 2/3] use lowercase either constructors

---
 lib/src/either.dart | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/src/either.dart b/lib/src/either.dart
index ee8dbd2..eca9353 100644
--- a/lib/src/either.dart
+++ b/lib/src/either.dart
@@ -215,9 +215,9 @@ Either<dynamic, A> catching<A>(Function0<A> thunk) {
 
 Future<Either<dynamic, A>> catchAsync<A>(Function0<Future<A>> f) async {
   try {
-    return Right(await f());
+    return right(await f());
   } catch (e) {
-    return Left(e);
+    return left(e);
   }
 }
 

From fcb65dd1426bf33c064a84419bf39a70632fccc5 Mon Sep 17 00:00:00 2001
From: otto-dev <ignatius.public@gmail.com>
Date: Sat, 16 Apr 2022 08:17:07 +1000
Subject: [PATCH 3/3] Allow method bodies that return FutureOr

---
 lib/src/either.dart   | 2 +-
 test/either_test.dart | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/src/either.dart b/lib/src/either.dart
index eca9353..774f814 100644
--- a/lib/src/either.dart
+++ b/lib/src/either.dart
@@ -213,7 +213,7 @@ Either<dynamic, A> catching<A>(Function0<A> thunk) {
   }
 }
 
-Future<Either<dynamic, A>> catchAsync<A>(Function0<Future<A>> f) async {
+Future<Either<dynamic, A>> catchAsync<A>(Function0<FutureOr<A>> f) async {
   try {
     return right(await f());
   } catch (e) {
diff --git a/test/either_test.dart b/test/either_test.dart
index e2c66c5..e1be8da 100644
--- a/test/either_test.dart
+++ b/test/either_test.dart
@@ -118,5 +118,13 @@ void main() {
       final error = Exception("foobar");
       expect(await catchAsync(() => throw error), left(error));
     });
+
+    test("value from async function", () async {
+      expect(await catchAsync(() async => 2), right(2));
+    });
+
+    test("value from sync function", () async {
+      expect(await catchAsync(() => 2), right(2));
+    });
   });
 }