diff --git a/Cargo.lock b/Cargo.lock
index b25fecd19..a8635013a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1783,6 +1783,7 @@ dependencies = [
  "napi-derive",
  "oxc_allocator",
  "oxc_codegen",
+ "oxc_diagnostics",
  "oxc_isolated_declarations",
  "oxc_parser",
  "oxc_span",
diff --git a/napi/transform/Cargo.toml b/napi/transform/Cargo.toml
index 6d63835d8..d2099b423 100644
--- a/napi/transform/Cargo.toml
+++ b/napi/transform/Cargo.toml
@@ -27,6 +27,7 @@ oxc_span                  = { workspace = true }
 oxc_codegen               = { workspace = true }
 oxc_isolated_declarations = { workspace = true }
 oxc_transformer           = { workspace = true }
+oxc_diagnostics           = { workspace = true }
 
 napi        = { workspace = true }
 napi-derive = { workspace = true }
diff --git a/napi/transform/src/lib.rs b/napi/transform/src/lib.rs
index 1bcabab17..99bfeab12 100644
--- a/napi/transform/src/lib.rs
+++ b/napi/transform/src/lib.rs
@@ -1,9 +1,12 @@
 pub mod transformer;
 
+use std::sync::Arc;
+
 use napi_derive::napi;
 
 use oxc_allocator::Allocator;
 use oxc_codegen::CodeGenerator;
+use oxc_diagnostics::{Error, NamedSource};
 use oxc_isolated_declarations::IsolatedDeclarations;
 use oxc_parser::Parser;
 use oxc_span::SourceType;
@@ -18,7 +21,7 @@ pub struct IsolatedDeclarationsResult {
 #[allow(clippy::needless_pass_by_value)]
 #[napi]
 pub fn isolated_declaration(filename: String, source_text: String) -> IsolatedDeclarationsResult {
-    let source_type = SourceType::from_path(filename).unwrap_or_default().with_typescript(true);
+    let source_type = SourceType::from_path(&filename).unwrap_or_default().with_typescript(true);
     let allocator = Allocator::default();
     let parser_ret = Parser::new(&allocator, &source_text, source_type).parse();
     let transformed_ret = IsolatedDeclarations::new(&allocator).build(&parser_ret.program);
@@ -26,12 +29,14 @@ pub fn isolated_declaration(filename: String, source_text: String) -> IsolatedDe
 
     let mut errors = vec![];
     if !parser_ret.errors.is_empty() || !transformed_ret.errors.is_empty() {
+        let source = Arc::new(NamedSource::new(filename, source_text.to_string()));
         errors.extend(
             parser_ret
                 .errors
                 .into_iter()
                 .chain(transformed_ret.errors)
-                .map(|error| error.message.to_string()),
+                .map(|diagnostic| Error::from(diagnostic).with_source_code(Arc::clone(&source)))
+                .map(|error| format!("{error:?}")),
         );
     }
 
diff --git a/napi/transform/test.mjs b/napi/transform/test.mjs
index f82e2b644..c7bbcc6e8 100644
--- a/napi/transform/test.mjs
+++ b/napi/transform/test.mjs
@@ -6,7 +6,10 @@ console.log(`Testing on ${process.platform}-${process.arch}`)
 test(oxc.isolatedDeclaration("test.ts", "class A {}"), "declare class A {}\n");
 
 function test(ret, expected) {
-  console.log(ret);
+  console.log(ret.sourceText);
+  for (const error of ret.errors) {
+    console.log(error)
+  }
   assert.equal(ret.sourceText, expected);
   assert(ret.errors.length == 0);
 }