Improve code quality and write tests

node_modules/regexp-tree/dist/interpreter/finite-automaton/special-symbols.js

@@ -0,0 +1,22 @@
+/**
+ * The MIT License (MIT)
+ * Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
+ */
+
+'use strict';
+
+/**
+ * Epsilon, the empty string.
+ */
+
+var EPSILON = 'ε';
+
+/**
+ * Epsilon-closure.
+ */
+var EPSILON_CLOSURE = EPSILON + '*';
+
+module.exports = {
+  EPSILON: EPSILON,
+  EPSILON_CLOSURE: EPSILON_CLOSURE
+};