JS: fix memory bug in ast.JSString() function

js/ast_test.go

@@ -122,7 +122,9 @@ func TestJS(t *testing.T) {
 		{"(t)=>{//!\n}", "(t) => { //! };"}, // space after //! is newline
 		{"import();", "import();"},
 		{"0\n.k", "(0).k;"},
-		{"do//!\n; while(1)", "//! do; while (1);"}, // space after //! is newline
+		{"do//!\n; while(1)", "//! do; while (1);"},           // space after //! is newline
+		{"//!\nn=>{ return n }", "//! (n) => { return n; };"}, // space after //! is newline
+		{"//!\n{//!\n}", "//! { //! }"},                       // space after //! is newline
 	}
 
 	re := regexp.MustCompile("\n *")

js/parse.go

@@ -636,6 +636,7 @@ func (p *Parser) parseStmt(allowDeclaration bool) (stmt IStmt) {
 }
 
 func (p *Parser) parseStmtList(in string) (list []IStmt) {
+	comments := len(p.comments)
 	if !p.consume(in, OpenBraceToken) {
 		return
 	}
@@ -649,9 +650,12 @@ func (p *Parser) parseStmtList(in string) (list []IStmt) {
 		}
 		list = append(list, p.parseStmt(true))
 	}
-	if 0 < len(p.comments) {
-		list = append(p.comments, list...)
-		p.comments = p.comments[:0]
+	if comments < len(p.comments) {
+		list2 := make([]IStmt, 0, len(p.comments)-comments+len(list))
+		list2 = append(list2, p.comments[comments:]...)
+		list2 = append(list2, list...)
+		list = list2
+		p.comments = p.comments[:comments]
 	}
 	return
 }