add all frontend files

node_modules/es-abstract/2019/modulo.js

@@ -0,0 +1,9 @@
+'use strict';
+
+var mod = require('../helpers/mod');
+
+// https://262.ecma-international.org/5.1/#sec-5.2
+
+module.exports = function modulo(x, y) {
+	return mod(x, y);
+};