From 37e077a6679a17fcec2f3f86df4e74b4237a91f4 Mon Sep 17 00:00:00 2001
From: Marcelo Lazaroni <lazaronijunior@gmail.com>
Date: Mon, 24 Nov 2025 22:08:39 +0000
Subject: [PATCH 1/3] Implement fromNullable for Maybe

---
 ambar-core/src/maybe.ts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/ambar-core/src/maybe.ts b/ambar-core/src/maybe.ts
index 2e5a9e3..0cbf62c 100644
--- a/ambar-core/src/maybe.ts
+++ b/ambar-core/src/maybe.ts
@@ -21,6 +21,7 @@ export {
   CallableJust as Just,
   CallableNothing as Nothing,
   from,
+  fromNullable,
   catMaybes,
   mapMaybe,
 };
@@ -99,6 +100,14 @@ function from<T>(v: undefined | T): Maybe<T> {
   }
 }
 
+function fromNullable<T>(v: Nullable<T>): Maybe<T> {
+  if (typeof v === null) {
+    return new Nothing();
+  } else {
+    return new Just(v as T);
+  }
+}
+
 // Remove Nothings from an array.
 function catMaybes<T>(xs: Array<Maybe<T>>): Array<T> {
   const r: Array<T> = [];

From 0812e5fdc0b60be0ec8796584c00dd514e2ef3ee Mon Sep 17 00:00:00 2001
From: Marcelo Lazaroni <lazaronijunior@gmail.com>
Date: Mon, 24 Nov 2025 22:14:43 +0000
Subject: [PATCH 2/3] Fix implementation

---
 ambar-core/src/maybe.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ambar-core/src/maybe.ts b/ambar-core/src/maybe.ts
index 0cbf62c..0bdc796 100644
--- a/ambar-core/src/maybe.ts
+++ b/ambar-core/src/maybe.ts
@@ -100,11 +100,11 @@ function from<T>(v: undefined | T): Maybe<T> {
   }
 }
 
-function fromNullable<T>(v: Nullable<T>): Maybe<T> {
-  if (typeof v === null) {
+function fromNullable<T>(v: T | null): Maybe<T> {
+  if (v === null) {
     return new Nothing();
   } else {
-    return new Just(v as T);
+    return new Just(v);
   }
 }
 

From 0984bfd83bec9652b125c3fdf3c498c97103b0d9 Mon Sep 17 00:00:00 2001
From: Marcelo Lazaroni <lazaronijunior@gmail.com>
Date: Mon, 24 Nov 2025 23:35:20 +0000
Subject: [PATCH 3/3] Add NonNullable constraint

---
 ambar-core/src/maybe.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ambar-core/src/maybe.ts b/ambar-core/src/maybe.ts
index 0bdc796..1feba96 100644
--- a/ambar-core/src/maybe.ts
+++ b/ambar-core/src/maybe.ts
@@ -100,7 +100,7 @@ function from<T>(v: undefined | T): Maybe<T> {
   }
 }
 
-function fromNullable<T>(v: T | null): Maybe<T> {
+function fromNullable<T>(v: NonNullable<T> | null): Maybe<T> {
   if (v === null) {
     return new Nothing();
   } else {