From 231b8f094661b9967421b54cb389b18ea6ce7b58 Mon Sep 17 00:00:00 2001
From: Dunqing <29533304+Dunqing@users.noreply.github.com>
Date: Fri, 21 Jun 2024 10:20:24 +0000
Subject: [PATCH] feat(isolated-declarations): support for export default
 function overloads (#3809)

---
 crates/oxc_isolated_declarations/src/lib.rs    | 16 ++++++++++++++++
 crates/oxc_isolated_declarations/tests/deno.rs | 15 +++++++--------
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/crates/oxc_isolated_declarations/src/lib.rs b/crates/oxc_isolated_declarations/src/lib.rs
index 3b2c33e07d2fe..a9e4da97a3b44 100644
--- a/crates/oxc_isolated_declarations/src/lib.rs
+++ b/crates/oxc_isolated_declarations/src/lib.rs
@@ -328,6 +328,7 @@ impl<'a> IsolatedDeclarations<'a> {
         stmts: oxc_allocator::Vec<'a, Statement<'a>>,
     ) -> impl Iterator<Item = Statement<'a>> + '_ {
         let mut last_function_name: Option<Atom<'a>> = None;
+        let mut is_export_default_function_overloads = false;
 
         stmts.into_iter().filter_map(move |stmt| match stmt {
             Statement::FunctionDeclaration(ref func) => {
@@ -373,6 +374,21 @@ impl<'a> IsolatedDeclarations<'a> {
                     Some(stmt)
                 }
             }
+            Statement::ExportDefaultDeclaration(ref decl) => {
+                if let ExportDefaultDeclarationKind::FunctionDeclaration(ref func) =
+                    decl.declaration
+                {
+                    if is_export_default_function_overloads && func.body.is_some() {
+                        is_export_default_function_overloads = false;
+                        return None;
+                    }
+                    is_export_default_function_overloads = true;
+                    Some(stmt)
+                } else {
+                    is_export_default_function_overloads = false;
+                    Some(stmt)
+                }
+            }
             _ => Some(stmt),
         })
     }
diff --git a/crates/oxc_isolated_declarations/tests/deno.rs b/crates/oxc_isolated_declarations/tests/deno.rs
index ff5f692528836..e371e28f61d72 100644
--- a/crates/oxc_isolated_declarations/tests/deno.rs
+++ b/crates/oxc_isolated_declarations/tests/deno.rs
@@ -360,14 +360,13 @@ export function foo(a: any): number {
             "export default function(a: number, b: number): number {};",
             "export default function(a: number, b: number): number;",
         );
-        // TODO export default function overloads
-        //         transform_dts_test(
-        //             "export default function(a: number, b: number): number;
-        // export default function(a: number, b: number): any {
-        //   return foo
-        // };",
-        //             "export default function(a: number, b: number): number;",
-        //         );
+        transform_dts_test(
+            "export default function(a: number, b: number): number;
+        export default function(a: number, b: number): any {
+          return foo
+        };",
+            "export default function(a: number, b: number): number;",
+        );
         transform_dts_test(
             "export default class {foo = 2};",
             "export default class {\n  foo: number;\n}",