Improve code quality and write tests

node_modules/@babel/helper-regex/lib/index.js

@@ -0,0 +1,30 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.is = is;
+exports.pullFlag = pullFlag;
+
+function _pull() {
+  const data = _interopRequireDefault(require("lodash/pull"));
+
+  _pull = function () {
+    return data;
+  };
+
+  return data;
+}
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+function is(node, flag) {
+  return node.type === "RegExpLiteral" && node.flags.indexOf(flag) >= 0;
+}
+
+function pullFlag(node, flag) {
+  const flags = node.flags.split("");
+  if (node.flags.indexOf(flag) < 0) return;
+  (0, _pull().default)(flags, flag);
+  node.flags = flags.join("");
+}