From a8c030feb51b0984fac5366de94fd2e1c160c1df Mon Sep 17 00:00:00 2001
From: Yorkin <cyb_yorkin@outlook.com>
Date: Mon, 10 Feb 2025 11:34:49 +0800
Subject: [PATCH] add optional type

fix mbti
---
 moon.mod.json       |  2 +-
 src/js/js.mbti      |  9 +++++++++
 src/js/optional.mbt | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 src/js/optional.mbt

diff --git a/moon.mod.json b/moon.mod.json
index 6daab3b..b0b28ca 100644
--- a/moon.mod.json
+++ b/moon.mod.json
@@ -1,6 +1,6 @@
 {
   "name": "rami3l/js-ffi",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "readme": "README.md",
   "repository": "",
   "license": "Apache-2.0",
diff --git a/src/js/js.mbti b/src/js/js.mbti
index f1b279a..14f32dd 100644
--- a/src/js/js.mbti
+++ b/src/js/js.mbti
@@ -51,6 +51,15 @@ impl Object {
   op_set[K, V](Self, K, V) -> Unit
 }
 
+type Optional[_]
+impl Optional {
+  from_option[T](T?) -> Self[T]
+  get_exn[T](Self[T]) -> T
+  is_undefined[T](Self[T]) -> Bool
+  to_option[T](Self[T]) -> T?
+  undefined[T]() -> Self[T]
+}
+
 pub type Promise[_]
 
 type Symbol
diff --git a/src/js/optional.mbt b/src/js/optional.mbt
new file mode 100644
index 0000000..841829b
--- /dev/null
+++ b/src/js/optional.mbt
@@ -0,0 +1,32 @@
+///|
+type Optional[_]
+
+///|
+pub fn Optional::is_undefined[T](self : Optional[T]) -> Bool {
+  self |> Value::cast_from |> Value::is_undefined
+}
+
+///|
+pub fn Optional::get_exn[T](self : Optional[T]) -> T = "%identity"
+
+///|
+pub fn Optional::to_option[T](self : Optional[T]) -> T? {
+  if Value::cast_from(self).is_undefined() {
+    None
+  } else {
+    Some(self.get_exn())
+  }
+}
+
+///|
+pub fn Optional::undefined[T]() -> Optional[T] {
+  Value::undefined().cast()
+}
+
+///|
+pub fn Optional::from_option[T](value : T?) -> Optional[T] {
+  match value {
+    Some(v) => Value::cast_from(v).cast()
+    None => Optional::undefined()
+  }
+}