From a562561286f26012e228e52e503bb40f83cba843 Mon Sep 17 00:00:00 2001
From: Gustavo Shigueo <gustavo.gsmn@gmail.com>
Date: Sun, 10 Nov 2024 19:41:55 -0300
Subject: [PATCH] Turn Optional into an enum

---
 macros/src/attr/field.rs  |  9 +++------
 macros/src/attr/mod.rs    | 30 +++++++++++++++++++++++-------
 macros/src/attr/struct.rs |  5 +----
 macros/src/types/named.rs | 26 +++++++-------------------
 4 files changed, 34 insertions(+), 36 deletions(-)

diff --git a/macros/src/attr/field.rs b/macros/src/attr/field.rs
index bf255757..8994bd66 100644
--- a/macros/src/attr/field.rs
+++ b/macros/src/attr/field.rs
@@ -55,10 +55,7 @@ impl Attr for FieldAttr {
             rename: self.rename.or(other.rename),
             inline: self.inline || other.inline,
             skip: self.skip || other.skip,
-            optional: Optional {
-                optional: self.optional.optional || other.optional.optional,
-                nullable: self.optional.nullable || other.optional.nullable,
-            },
+            optional: self.optional.or(other.optional),
             flatten: self.flatten || other.flatten,
 
             using_serde_with: self.using_serde_with || other.using_serde_with,
@@ -124,7 +121,7 @@ impl Attr for FieldAttr {
                 );
             }
 
-            if self.optional.optional {
+            if let Optional::Optional { .. } = self.optional {
                 syn_err_spanned!(
                     field;
                     "`optional` is not compatible with `flatten`"
@@ -147,7 +144,7 @@ impl Attr for FieldAttr {
                 );
             }
 
-            if self.optional.optional {
+            if let Optional::Optional { .. } = self.optional {
                 syn_err_spanned!(
                     field;
                     "`optional` cannot with tuple struct fields"
diff --git a/macros/src/attr/mod.rs b/macros/src/attr/mod.rs
index de2d4f08..61debed4 100644
--- a/macros/src/attr/mod.rs
+++ b/macros/src/attr/mod.rs
@@ -19,9 +19,28 @@ mod variant;
 /// `#[ts(optional)]` turns an `t: Option<T>` into `t?: T`, while
 /// `#[ts(optional = nullable)]` turns it into `t?: T | null`.
 #[derive(Default, Clone, Copy)]
-pub struct Optional {
-    pub optional: bool,
-    pub nullable: bool,
+pub enum Optional {
+    Optional {
+        nullable: bool,
+    },
+
+    #[default]
+    NotOptional,
+}
+
+impl Optional {
+    pub fn or(self, other: Optional) -> Self {
+        match (self, other) {
+            (Self::NotOptional, Self::NotOptional) => Self::NotOptional,
+
+            (Self::Optional { nullable }, Self::NotOptional)
+            | (Self::NotOptional, Self::Optional { nullable }) => Self::Optional { nullable },
+
+            (Self::Optional { nullable: a }, Self::Optional { nullable: b }) => {
+                Self::Optional { nullable: a || b }
+            }
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -202,8 +221,5 @@ fn parse_optional(input: ParseStream) -> Result<Optional> {
         false
     };
 
-    Ok(Optional {
-        optional: true,
-        nullable,
-    })
+    Ok(Optional::Optional { nullable })
 }
diff --git a/macros/src/attr/struct.rs b/macros/src/attr/struct.rs
index 5a693574..9cd74054 100644
--- a/macros/src/attr/struct.rs
+++ b/macros/src/attr/struct.rs
@@ -91,10 +91,7 @@ impl Attr for StructAttr {
                 (Some(bound), None) | (None, Some(bound)) => Some(bound),
                 (None, None) => None,
             },
-            optional: Optional {
-                optional: self.optional.optional || other.optional.optional,
-                nullable: self.optional.nullable || other.optional.nullable,
-            },
+            optional: self.optional.or(other.optional),
         }
     }
 
diff --git a/macros/src/types/named.rs b/macros/src/types/named.rs
index e6267144..737baf85 100644
--- a/macros/src/types/named.rs
+++ b/macros/src/types/named.rs
@@ -105,30 +105,18 @@ fn format_field(
     let ty = field_attr.type_as(&field.ty);
 
     let opt = match (struct_optional, field_attr.optional) {
-        (
-            opt @ Optional { optional: true, .. },
-            Optional {
-                optional: false, ..
-            },
-        ) => opt,
-        (_, opt @ Optional { optional: true, .. }) => opt,
-        (
-            opt @ Optional {
-                optional: false, ..
-            },
-            Optional {
-                optional: false, ..
-            },
-        ) => opt,
+        (opt @ Optional::Optional { .. }, Optional::NotOptional) => opt,
+        (_, opt @ Optional::Optional { .. }) => opt,
+        (opt @ Optional::NotOptional, Optional::NotOptional) => opt,
     };
 
-    let optional_annotation = if opt.optional {
+    let optional_annotation = if let Optional::Optional { .. } = opt {
         quote! { if <#ty as #crate_rename::TS>::IS_OPTION { "?" } else { "" } }
     } else {
         quote! { "" }
     };
 
-    let optional_annotation = if field_attr.optional.optional {
+    let optional_annotation = if let Optional::Optional { .. } = field_attr.optional {
         quote! {
             if <#ty as #crate_rename::TS>::IS_OPTION {
                 #optional_annotation
@@ -153,7 +141,7 @@ fn format_field(
             if field_attr.inline {
                 dependencies.append_from(&ty);
 
-                if opt.optional && !opt.nullable {
+                if let Optional::Optional { nullable: false } = opt {
                     quote! {
                         if <#ty as #crate_rename::TS>::IS_OPTION {
                             <#ty as #crate_rename::TS>::option_inner_inline().unwrap()
@@ -166,7 +154,7 @@ fn format_field(
                 }
             } else {
                 dependencies.push(&ty);
-                if opt.optional && !opt.nullable {
+                if let Optional::Optional { nullable: false } = opt {
                     quote! {
                         if <#ty as #crate_rename::TS>::IS_OPTION {
                             <#ty as #crate_rename::TS>::option_inner_name().unwrap()