Babel w/o getPrototypeOf

input.js

delete Object.getPrototypeOf
delete Object.setPrototypeOf

class A extends null {
  constructor(arg) {
    console.log(arg)
    return Object.create(new.target.prototype);
  }
}

class B extends A {}

var a = new A('a')
var b = new B('b')

output.js

"use strict";

function _typeof(obj) { "@babel/helpers - typeof"; if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }; } return _typeof(obj); }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function"); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, writable: true, configurable: true } }); if (superClass) _setPrototypeOf(subClass, superClass); }

function _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }

function _createSuper(Derived) { var hasNativeReflectConstruct = _isNativeReflectConstruct(); return function _createSuperInternal() { var Super = _getPrototypeOf(Derived), result; if (hasNativeReflectConstruct) { var NewTarget = _getPrototypeOf(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return _possibleConstructorReturn(this, result); }; }

function _possibleConstructorReturn(self, call) { if (call && (_typeof(call) === "object" || typeof call === "function")) { return call; } return _assertThisInitialized(self); }

function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }

function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Date.prototype.toString.call(Reflect.construct(Date, [], function () {})); return true; } catch (e) { return false; } }

function _getPrototypeOf(o) { _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf : function _getPrototypeOf(o) { return o.__proto__ || Object.getPrototypeOf(o); }; return _getPrototypeOf(o); }

delete Object.getPrototypeOf;
delete Object.setPrototypeOf;

var A = /*#__PURE__*/function (_ref) {
  _inherits(A, _ref);

  var _super = _createSuper(A);

  function A(arg) {
    var _this;

    _classCallCheck(this, A);

    console.log(arg);
    return _possibleConstructorReturn(_this, Object.create((this instanceof A ? this.constructor : void 0).prototype));
  }

  return A;
}(null);

var B = /*#__PURE__*/function (_A) {
  _inherits(B, _A);

  var _super2 = _createSuper(B);

  function B() {
    _classCallCheck(this, B);

    return _super2.apply(this, arguments);
  }

  return B;
}(A);

var a = new A('a');
var b = new B('b');