webpack vs. rollup

0-src.js

export default {}

rollup.umd.js

(function(global, factory) {
  typeof exports === "object" && typeof module !== "undefined" ? module.exports = factory() : typeof define === "function" && define.amd ? define(factory) : global.Stimulus = factory();
})(this, function() {
  "use strict";
  var index = {};
  return index;
});

webpack.umd.js

(function webpackUniversalModuleDefinition(root, factory) {
  if (typeof exports === "object" && typeof module === "object") module.exports = factory(); else if (typeof define === "function" && define.amd) define([], factory); else if (typeof exports === "object") exports["Stimulus"] = factory(); else root["Stimulus"] = factory();
})(typeof self !== "undefined" ? self : this, function() {
  return function(modules) {
    var installedModules = {};
    function __webpack_require__(moduleId) {
      if (installedModules[moduleId]) {
        return installedModules[moduleId].exports;
      }
      var module = installedModules[moduleId] = {
        i: moduleId,
        l: false,
        exports: {}
      };
      modules[moduleId].call(module.exports, module, module.exports, __webpack_require__);
      module.l = true;
      return module.exports;
    }
    __webpack_require__.m = modules;
    __webpack_require__.c = installedModules;
    __webpack_require__.d = function(exports, name, getter) {
      if (!__webpack_require__.o(exports, name)) {
        Object.defineProperty(exports, name, {
          configurable: false,
          enumerable: true,
          get: getter
        });
      }
    };
    __webpack_require__.n = function(module) {
      var getter = module && module.__esModule ? function getDefault() {
        return module["default"];
      } : function getModuleExports() {
        return module;
      };
      __webpack_require__.d(getter, "a", getter);
      return getter;
    };
    __webpack_require__.o = function(object, property) {
      return Object.prototype.hasOwnProperty.call(object, property);
    };
    __webpack_require__.p = "";
    return __webpack_require__(__webpack_require__.s = 0);
  }([ function(module, __webpack_exports__, __webpack_require__) {
    "use strict";
    Object.defineProperty(__webpack_exports__, "__esModule", {
      value: true
    });
    __webpack_exports__["default"] = {};
  } ]);
});