fix(codegen): missing , when generating type parameters with jsx (#7929)

close: #7917

crates/oxc_codegen/src/gen.rs

@@ -38,6 +38,8 @@ pub trait GenExpr: GetSpan {
 
 impl Gen for Program<'_> {
     fn gen(&self, p: &mut Codegen, ctx: Context) {
+        p.is_jsx = self.source_type.is_jsx();
+
         if let Some(hashbang) = &self.hashbang {
             hashbang.print(p, ctx);
         }
@@ -2976,6 +2978,10 @@ impl Gen for TSTypeParameterDeclaration<'_> {
             p.print_soft_newline();
             p.dedent();
             p.print_indent();
+        } else if p.is_jsx {
+            // `<T,>() => {}`
+            //    ^ We need a comma here, otherwise it will be regarded as a JSX element.
+            p.print_str(",");
         }
         p.print_ascii_byte(b'>');
     }

crates/oxc_codegen/src/lib.rs

@@ -89,6 +89,9 @@ pub struct Codegen<'a> {
     need_space_before_dot: usize,
     print_next_indent_as_space: bool,
     binary_expr_stack: Vec<BinaryExpressionVisitor<'a>>,
+    /// Indicates the output is JSX type, it is set in [`Program::gen`] and the result
+    /// is obtained by [`oxc_span::SourceType::is_jsx`]
+    is_jsx: bool,
 
     /// For avoiding `;` if the previous statement ends with `}`.
     needs_semicolon: bool,
@@ -170,6 +173,7 @@ impl<'a> Codegen<'a> {
             start_of_stmt: 0,
             start_of_arrow_expr: 0,
             start_of_default_export: 0,
+            is_jsx: false,
             indent: 0,
             quote: b'"',
             print_comments,

crates/oxc_codegen/tests/integration/tester.rs

@@ -8,7 +8,24 @@ pub fn test(source_text: &str, expected: &str) {
 }
 
 pub fn test_options(source_text: &str, expected: &str, options: CodegenOptions) {
-    let source_type = SourceType::jsx();
+    test_options_with_source_type(source_text, expected, SourceType::jsx(), options);
+}
+
+pub fn test_tsx(source_text: &str, expected: &str) {
+    test_options_with_source_type(
+        source_text,
+        expected,
+        SourceType::tsx(),
+        CodegenOptions::default(),
+    );
+}
+
+pub fn test_options_with_source_type(
+    source_text: &str,
+    expected: &str,
+    source_type: SourceType,
+    options: CodegenOptions,
+) {
     let allocator = Allocator::default();
     let ret = Parser::new(&allocator, source_text, source_type).parse();
     let result = CodeGenerator::new().with_options(options).build(&ret.program).code;

crates/oxc_codegen/tests/integration/ts.rs

@@ -1,6 +1,6 @@
 use oxc_codegen::CodegenOptions;
 
-use crate::{snapshot, snapshot_options};
+use crate::{snapshot, snapshot_options, tester::test_tsx};
 
 #[test]
 fn ts() {
@@ -99,3 +99,9 @@ export { default as name16 } from "module-name";
         &CodegenOptions { minify: true, ..CodegenOptions::default() },
     );
 }
+
+#[test]
+fn tsx() {
+    test_tsx("<T,>() => {}", "<T,>() => {};\n");
+    test_tsx("<T, B>() => {}", "<\n\tT,\n\tB\n>() => {};\n");
+}