FIX

react-navigation/react-navigation#6179 (comment)

This project shows how react-native can work correctly in web. The only problem I have found is that I get this error when running the web production build:

createNavigator.js:4 Uncaught TypeError: Cannot read property 'default' of undefined
    at new f (createNavigator.js:4)
    at lo (react-dom.production.min.js:2827)
    at Ci (react-dom.production.min.js:3759)
    at Li (react-dom.production.min.js:3960)
    at Ya (react-dom.production.min.js:5514)
    at Xa (react-dom.production.min.js:5536)
    at Rs (react-dom.production.min.js:5958)
    at ks (react-dom.production.min.js:5925)
    at Es (react-dom.production.min.js:5860)
    at Ja (react-dom.production.min.js:5787)

Un-minified code

When I disable minification in the production build (ret.optimization.minimize = false; in config-overrides.js), this is the code that gets generated, specifically for the createNavigator.js file.

There is a variable, _getPrototypeOf2, that gets declared first with a correct value, but then gets redeclared var _getPrototypeOf2; and is not assigned a new value.

This causes the error further down in the function.

(function(module, exports, __webpack_require__) {

    var _interopRequireDefault = __webpack_require__(3);
    Object.defineProperty(exports, "__esModule", {
        value: true
    });
    exports.default = void 0;
    var _extends2 = _interopRequireDefault(__webpack_require__(23));
    var _classCallCheck2 = _interopRequireDefault(__webpack_require__(17));
    var _createClass2 = _interopRequireDefault(__webpack_require__(18));
    var _possibleConstructorReturn2 = _interopRequireDefault(__webpack_require__(19));

    // This is the original declaration of the variable
    // This declaration has a correct value that works without errors
    var _getPrototypeOf2 = _interopRequireDefault(__webpack_require__(20));

    var _inherits2 = _interopRequireDefault(__webpack_require__(21));
    var _react = _interopRequireDefault(__webpack_require__(1));
    var _invariant = _interopRequireDefault(__webpack_require__(46));
    var _jsxFileName = "/Users/brentvatne/coding/react-navigation-core/src/navigators/createNavigator.js";
    function createNavigator(NavigatorView, router, navigationConfig) {
        var Navigator = function(_React$Component) {
            (0,
            _inherits2.default)(Navigator, _React$Component);
            function Navigator() {
                // This is the re-declaration of the variable
                // If you remove this line in the generated js bundle, the app runs without errors
                // If you assign the value of the original _getPrototypeOf2 declaration the app also works (if you do this you have to rename the variable from the first declaration)
                var _getPrototypeOf2;
                var _this;
                (0,
                _classCallCheck2.default)(this, Navigator);
                for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
                    args[_key] = arguments[_key];
                }

                // It fails on this line, when evaluating _getPrototypeOf2.default
                _this = (0,
                _possibleConstructorReturn2.default)(this, (_getPrototypeOf2 = (0,
                _getPrototypeOf2.default)(Navigator)).call.apply(_getPrototypeOf2, [this].concat(args)));
                _this.state = {
                    descriptors: {},
                    screenProps: _this.props.screenProps
                };
                return _this;
            }
// ...

Minified code

When building the minified js bundle, a similar modification allows the app to work. The first declaration of var _getPrototypeOf2 = _interopRequireDefault(__webpack_require__(20)); is minified to l = (r(n(20)), r(n(21))). (Since the value of that require is never user, the declaration is omitted, but the call to require is still executed).

The second declaration of the variable (var _getPrototypeOf2;) is converted to var e, t;, where e is used as _getPrototypeOf2;

If you modify var e, t; to var e=any_var,t; and l = (r(n(20)), r(n(21))) to any_var = r(n(20)), l = r(n(21)), the app works fine. What this does is basically give a value to the variable that was declared without a value.