diff --git a/vlib/compiler/parser.v b/vlib/compiler/parser.v
index b514b217dc..0ccef455cc 100644
--- a/vlib/compiler/parser.v
+++ b/vlib/compiler/parser.v
@@ -3385,7 +3385,9 @@ fn (p mut Parser) for_st() {
 			})
 			// TODO don't generate if it's not used.
 			// Otherwise it's a C warning + perf.
-			p.genln('bool last = $i == $tmp . len - 1;')
+			if !p.is_js {
+				p.genln('bool last = $i == $tmp . len - 1;')
+			}
 		}
 		else if is_str {
 			typ = 'byte'