node_modules/core-js/modules/es6.regexp.to-string.js

'use strict';
require('./es6.regexp.flags');
var anObject = require('./_an-object');
var $flags = require('./_flags');
var DESCRIPTORS = require('./_descriptors');
var TO_STRING = 'toString';
var $toString = /./[TO_STRING];

var define = function (fn) {
  require('./_redefine')(RegExp.prototype, TO_STRING, fn, true);
};

// 21.2.5.14 RegExp.prototype.toString()
if (require('./_fails')(function () { return $toString.call({ source: 'a', flags: 'b' }) != '/a/b'; })) {
  define(function toString() {
    var R = anObject(this);
    return '/'.concat(R.source, '/',
      'flags' in R ? R.flags : !DESCRIPTORS && R instanceof RegExp ? $flags.call(R) : undefined);
  });
// FF44- RegExp#toString has a wrong name
} else if ($toString.name != TO_STRING) {
  define(function toString() {
    return $toString.call(this);
  });
}