From 1856309d9d04cffcfeb42febf7e990daebd107ee Mon Sep 17 00:00:00 2001
From: Ashley Hunter <ashley.hunter@hotmail.co.uk>
Date: Sat, 21 Mar 2026 22:32:37 +0000
Subject: [PATCH] fix(compiler): strip abstract keyword from class expressions
 in JIT mode

---
 .../src/component/transform.rs                | 17 ++++++-
 .../tests/integration_test.rs                 | 46 +++++++++++++++++++
 .../integration_test__jit_abstract_class.snap | 21 +++++++++
 3 files changed, 82 insertions(+), 2 deletions(-)
 create mode 100644 crates/oxc_angular_compiler/tests/snapshots/integration_test__jit_abstract_class.snap

diff --git a/crates/oxc_angular_compiler/src/component/transform.rs b/crates/oxc_angular_compiler/src/component/transform.rs
index 636906434..c2bfbba42 100644
--- a/crates/oxc_angular_compiler/src/component/transform.rs
+++ b/crates/oxc_angular_compiler/src/component/transform.rs
@@ -695,6 +695,8 @@ struct JitClassInfo {
     is_exported: bool,
     /// Whether the class is export default.
     is_default_export: bool,
+    /// Whether the class is abstract.
+    is_abstract: bool,
     /// Constructor parameter info for ctorParameters.
     ctor_params: std::vec::Vec<JitCtorParam>,
     /// Member decorator info for propDecorators.
@@ -1224,6 +1226,7 @@ fn transform_angular_file_jit(
             class_body_end: class.body.span.end,
             is_exported,
             is_default_export,
+            is_abstract: class.r#abstract,
             ctor_params,
             member_decorators,
             decorator_text,
@@ -1343,15 +1346,25 @@ fn transform_angular_file_jit(
         }
 
         // 4c. Class restructuring: `export class X` → `let X = class X`
+        // For abstract classes, also strip the `abstract` keyword since class expressions can't be abstract.
+        let class_keyword_start = if jit_info.is_abstract {
+            let rest = &source[jit_info.class_start as usize..];
+            let offset = rest.find("class").unwrap_or(0);
+            jit_info.class_start + offset as u32
+        } else {
+            jit_info.class_start
+        };
+
         if jit_info.is_exported || jit_info.is_default_export {
             edits.push(Edit::replace(
                 jit_info.stmt_start,
-                jit_info.class_start,
+                class_keyword_start,
                 format!("let {} = ", jit_info.class_name),
             ));
         } else {
-            edits.push(Edit::insert(
+            edits.push(Edit::replace(
                 jit_info.class_start,
+                class_keyword_start,
                 format!("let {} = ", jit_info.class_name),
             ));
         }
diff --git a/crates/oxc_angular_compiler/tests/integration_test.rs b/crates/oxc_angular_compiler/tests/integration_test.rs
index 490d5c8e8..4be2806dc 100644
--- a/crates/oxc_angular_compiler/tests/integration_test.rs
+++ b/crates/oxc_angular_compiler/tests/integration_test.rs
@@ -6406,6 +6406,52 @@ export class TestComponent {
     insta::assert_snapshot!("jit_union_type_ctor_params", result.code);
 }
 
+#[test]
+fn test_jit_abstract_class() {
+    let allocator = Allocator::default();
+    let source = r#"
+import { Injectable } from '@angular/core';
+
+@Injectable()
+export abstract class BaseProvider {
+    protected abstract get name(): string;
+    protected abstract initialize(): void;
+
+    public greet(): string {
+        return `Hello from ${this.name}`;
+    }
+}
+"#;
+
+    let options = ComponentTransformOptions { jit: true, ..Default::default() };
+    let result = transform_angular_file(&allocator, "base.provider.ts", source, &options, None);
+    assert!(!result.has_errors(), "Should not have errors: {:?}", result.diagnostics);
+
+    // The abstract keyword should NOT appear before "class" in the output
+    // (JIT converts to class expression which can't be abstract)
+    assert!(
+        !result.code.contains("abstract class"),
+        "JIT output should not contain 'abstract class'. Got:\n{}",
+        result.code
+    );
+
+    // Should have proper class expression
+    assert!(
+        result.code.contains("let BaseProvider = class BaseProvider"),
+        "JIT output should have class expression. Got:\n{}",
+        result.code
+    );
+
+    // Should have __decorate call
+    assert!(
+        result.code.contains("__decorate("),
+        "JIT output should use __decorate. Got:\n{}",
+        result.code
+    );
+
+    insta::assert_snapshot!("jit_abstract_class", result.code);
+}
+
 // =========================================================================
 // Source map tests
 // =========================================================================
diff --git a/crates/oxc_angular_compiler/tests/snapshots/integration_test__jit_abstract_class.snap b/crates/oxc_angular_compiler/tests/snapshots/integration_test__jit_abstract_class.snap
new file mode 100644
index 000000000..0a54dbb93
--- /dev/null
+++ b/crates/oxc_angular_compiler/tests/snapshots/integration_test__jit_abstract_class.snap
@@ -0,0 +1,21 @@
+---
+source: crates/oxc_angular_compiler/tests/integration_test.rs
+assertion_line: 6452
+expression: result.code
+---
+
+import { Injectable } from '@angular/core';
+import { __decorate } from "tslib";
+
+let BaseProvider = class BaseProvider {
+    protected abstract get name(): string;
+    protected abstract initialize(): void;
+
+    public greet(): string {
+        return `Hello from ${this.name}`;
+    }
+};
+BaseProvider = __decorate([
+    Injectable()
+], BaseProvider);
+export { BaseProvider };