From 2e95cdb437422de686889bca0c4bf4cf69f53935 Mon Sep 17 00:00:00 2001
From: Ian McIntosh <cranston.ian@gmail.com>
Date: Mon, 6 Jun 2022 16:51:04 -0400
Subject: [PATCH] Add Task.fromEither

---
 lib/src/task.dart   |  2 ++
 test/task_test.dart | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/lib/src/task.dart b/lib/src/task.dart
index fbae897..efb2f42 100644
--- a/lib/src/task.dart
+++ b/lib/src/task.dart
@@ -11,6 +11,8 @@ class Task<A> implements MonadCatchOps<Task, A> {
 
   static Task<A> failed<A>(Object err) => new Task(() => new Future.error(err));
 
+  static Task<A> fromEither<A>(Either<Object, A> e) => e.fold((l) => Task.failed<A>(l), (r) => Task.value(r));
+
   static Task<void> sleep(Duration duration) => Task(() => Future.delayed(duration));
 
   static Task<void> print(String s) => Task.delay(() => _consolePrint(s));
diff --git a/test/task_test.dart b/test/task_test.dart
index cf2eba1..a0025b1 100644
--- a/test/task_test.dart
+++ b/test/task_test.dart
@@ -16,6 +16,21 @@ void main() {
     expect(result1, result2);
   });
 
+  test('Task.fromEither', () async {
+    final taskLeft = await Task.value(1000)
+        .productR(Task.fromEither(left<String, int>('boom')))
+        .attempt()
+        .run();
+
+    final taskRight = await Task.fromEither(right<String, int>(42))
+        .replace(1000)
+        .attempt()
+        .run();
+
+    expect(taskLeft, left('boom'));
+    expect(taskRight, right(1000));
+  });
+
   test("Task attempt", () async {
     final Task<Either<Object, num>> t =
         Task.delay(() => "notanumber").map(num.parse).attempt();