JS: support ellipsis operator anywhere in arguments

js/ast.go

@@ -1064,10 +1064,14 @@ func (n ImportMetaExpr) String() string {
 	return "(import.meta)"
 }
 
+type Arg struct {
+	Value IExpr
+	Rest  bool
+}
+
 // Args is a list of arguments as used by new and call expressions.
 type Args struct {
-	List []IExpr
-	Rest IExpr // can be nil
+	List []Arg
 }
 
 func (n Args) String() string {
@@ -1076,13 +1080,10 @@ func (n Args) String() string {
 		if i != 0 {
 			s += ", "
 		}
-		s += item.String()
-	}
-	if n.Rest != nil {
-		if len(n.List) != 0 {
-			s += ", "
+		if item.Rest {
+			s += "..."
 		}
-		s += "..." + n.Rest.String()
+		s += item.Value.String()
 	}
 	return s + ")"
 }

js/parse.go

@@ -1315,21 +1315,20 @@ func (p *Parser) parseTemplateLiteral(precLeft OpPrec) (template TemplateExpr) {
 func (p *Parser) parseArguments() (args Args) {
 	// assume we're on (
 	p.next()
-	args.List = make([]IExpr, 0, 4)
+	args.List = make([]Arg, 0, 4)
 	for {
-		if p.tt == EllipsisToken {
+		rest := p.tt == EllipsisToken
+		if rest {
 			p.next()
-			args.Rest = p.parseExpression(OpAssign)
-			if p.tt == CommaToken {
-				p.next()
-			}
-			break
 		}
 
 		if p.tt == CloseParenToken || p.tt == ErrorToken {
 			break
 		}
-		args.List = append(args.List, p.parseExpression(OpAssign))
+		args.List = append(args.List, Arg{
+			Value: p.parseExpression(OpAssign),
+			Rest:  rest,
+		})
 		if p.tt == CommaToken {
 			p.next()
 		}
@@ -1572,7 +1571,7 @@ func (p *Parser) parseExpression(prec OpPrec) IExpr {
 			newExpr := &NewExpr{p.parseExpression(OpNew), nil}
 			if p.tt == OpenParenToken {
 				args := p.parseArguments()
-				if len(args.List) != 0 || args.Rest != nil {
+				if len(args.List) != 0 {
 					newExpr.Args = &args
 				}
 				precLeft = OpMember

js/parse_test.go

@@ -250,6 +250,7 @@ func TestParse(t *testing.T) {
 		{"x = a?.(b)", "Stmt(x=(a?.(b)))"},
 		{"x = super(a)", "Stmt(x=(super(a)))"},
 		{"x = a(a,b,...c,)", "Stmt(x=(a(a, b, ...c)))"},
+		{"x = a(...a,...b)", "Stmt(x=(a(...a, ...b)))"},
 		{"x = new a", "Stmt(x=(new a))"},
 		{"x = new a()", "Stmt(x=(new a))"},
 		{"x = new a(b)", "Stmt(x=(new a(b)))"},