feat(minifier): fold undefined argument in non delegating yield (#27324)

add missing optimization for `yield undefined`,

`undefined` is substituted for `void 0` if its a global

---------

Co-authored-by: Cameron <cameron.clark@hey.com>

crates/oxc_minifier/src/peephole/mod.rs

@@ -590,7 +590,11 @@ impl<'a> Traverse<'a> for PeepholeOptimizations {
                     Self::substitute_unary_plus(expr, ctx);
                     Self::fold_sequence_expression(expr, ctx);
                 }
-                Expression::YieldExpression(_) | Expression::AwaitExpression(_) => {
+                Expression::YieldExpression(e) => {
+                    Self::substitute_yield_expression(e);
+                    Self::fold_sequence_expression(expr, ctx);
+                }
+                Expression::AwaitExpression(_) => {
                     Self::fold_sequence_expression(expr, ctx);
                 }
                 Expression::StaticMemberExpression(_) => {

crates/oxc_minifier/src/peephole/substitute_alternate_syntax.rs

@@ -1049,6 +1049,14 @@ impl<'a> PeepholeOptimizations {
         }
     }
 
+    /// Remove `void 0` from a non-delegating `yield`.
+    /// `yield void 0` -> `yield`
+    pub fn substitute_yield_expression(expr: &mut YieldExpression<'a>) {
+        if !expr.delegate && expr.argument.as_ref().is_some_and(Expression::is_void_0) {
+            expr.argument = None;
+        }
+    }
+
     fn compress_variable_declarator(
         decl: &mut VariableDeclarator<'a>,
         kind: VariableDeclarationKind,

crates/oxc_minifier/tests/peephole/substitute_alternate_syntax.rs

@@ -1115,7 +1115,7 @@ fn test_flatten_array_spread_elements() {
 }
 
 #[test]
-fn fold_sequence_expression() {
+fn test_fold_sequence_expression() {
     test("(a(), b) + c", "a(), b + c");
     test("(a(), b, c) + d", "a(), b, c + d");
 
@@ -1138,3 +1138,15 @@ fn fold_sequence_expression() {
         "async function a() { c(1), d(2), await 3 }",
     );
 }
+
+#[test]
+fn test_substitute_yield_expression() {
+    test("function* a() { yield 2 }", "function* a() { yield 2; }");
+    test("function* a() { yield void 0; }", "function* a() { yield; }");
+    test("function* a() { yield undefined; }", "function* a() { yield; }");
+    test("function* a() { yield fn(); }", "function* a() { yield fn(); }");
+    test_same("function* a() { yield* void 0; }");
+    test("function* a() { yield* undefined; }", "function* a() { yield* void 0; }");
+    test("function* a() { yield* fn(); }", "function* a() { yield* fn(); }");
+    test_same("function* a(undefined) { yield undefined; }");
+}