diff --git a/nginx/ngx_js.c b/nginx/ngx_js.c
index 84cdcc2eb..c91a55308 100644
--- a/nginx/ngx_js.c
+++ b/nginx/ngx_js.c
@@ -1482,13 +1482,11 @@ ngx_qjs_string(JSContext *cx, JSValueConst val, ngx_str_t *dst)
 
 string:
 
-    str = JS_ToCString(cx, val);
+    str = JS_ToCStringLen(cx, &len, val);
     if (str == NULL) {
         return NGX_ERROR;
     }
 
-    len = strlen(str);
-
     start = njs_mp_alloc(e->pool, len);
     if (start == NULL) {
         JS_FreeCString(cx, str);