Flutter Web Issue

main.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

main.dart.js

(function() {
  var _currentDirectory = (function () {
  var _url;
  var lines = new Error().stack.split('\n');
  function lookupUrl() {
    if (lines.length > 2) {
      var match = lines[1].match(/^\s+at (.+):\d+:\d+$/);
      // Chrome.
      if (match) return match[1];
      // Chrome nested eval case.
      match = lines[1].match(/^\s+at eval [(](.+):\d+:\d+[)]$/);
      if (match) return match[1];
      // Edge.
      match = lines[1].match(/^\s+at.+\((.+):\d+:\d+\)$/);
      if (match) return match[1];
      // Firefox.
      match = lines[0].match(/[<][@](.+):\d+:\d+$/)
      if (match) return match[1];
    }
    // Safari.
    return lines[0].match(/(.+):\d+:\d+$/)[1];
  }
  _url = lookupUrl();
  var lastSlash = _url.lastIndexOf('/');
  if (lastSlash == -1) return _url;
  var currentDirectory = _url.substring(0, lastSlash + 1);
  return currentDirectory;
})();

  var baseUrl = (function () {
  // Attempt to detect --precompiled mode for tests, and set the base url
  // appropriately, otherwise set it to '/'.
  var pathParts = location.pathname.split("/");
  if (pathParts[0] == "") {
    pathParts.shift();
  }
  if (pathParts.length > 1 && pathParts[1] == "test") {
    return "/" + pathParts.slice(0, 2).join("/") + "/";
  }
  // Attempt to detect base url using <base href> html tag
  // base href should start and end with "/"
  if (typeof document !== 'undefined') {
    var el = document.getElementsByTagName('base');
    if (el && el[0] && el[0].getAttribute("href") && el[0].getAttribute
    ("href").startsWith("/") && el[0].getAttribute("href").endsWith("/")){
      return el[0].getAttribute("href");
    }
  }
  // return default value
  return "/";
}());


  var mapperUri = baseUrl + "packages/build_web_compilers/src/" +
      "dev_compiler_stack_trace/stack_trace_mapper.dart.js";
  var requireUri = baseUrl +
      "packages/build_web_compilers/src/dev_compiler/require.js";
  var mainUri = _currentDirectory + "main_web_entrypoint.dart.bootstrap";

  if (typeof document != 'undefined') {
    var el = document.createElement("script");
    el.defer = true;
    el.async = false;
    el.src = mapperUri;
    document.head.appendChild(el);

    el = document.createElement("script");
    el.defer = true;
    el.async = false;
    el.src = requireUri;
    el.setAttribute("data-main", mainUri);
    document.head.appendChild(el);
  } else {
    importScripts(mapperUri, requireUri);
    require.config({
      baseUrl: baseUrl,
    });
    // TODO: update bootstrap code to take argument - dart-lang/build#1115
    window = self;
    require([mainUri + '.js']);
  }
})();

main_web_entrypoint.dart.bootstrap.js

/* ENTRYPOINT_EXTENTION_MARKER */
(function() {
var _currentDirectory = (function () {
  var _url;
  var lines = new Error().stack.split('\n');
  function lookupUrl() {
    if (lines.length > 2) {
      var match = lines[1].match(/^\s+at (.+):\d+:\d+$/);
      // Chrome.
      if (match) return match[1];
      // Chrome nested eval case.
      match = lines[1].match(/^\s+at eval [(](.+):\d+:\d+[)]$/);
      if (match) return match[1];
      // Edge.
      match = lines[1].match(/^\s+at.+\((.+):\d+:\d+\)$/);
      if (match) return match[1];
      // Firefox.
      match = lines[0].match(/[<][@](.+):\d+:\d+$/)
      if (match) return match[1];
    }
    // Safari.
    return lines[0].match(/(.+):\d+:\d+$/)[1];
  }
  _url = lookupUrl();
  var lastSlash = _url.lastIndexOf('/');
  if (lastSlash == -1) return _url;
  var currentDirectory = _url.substring(0, lastSlash + 1);
  return currentDirectory;
})();

var baseUrl = (function () {
  // Attempt to detect --precompiled mode for tests, and set the base url
  // appropriately, otherwise set it to '/'.
  var pathParts = location.pathname.split("/");
  if (pathParts[0] == "") {
    pathParts.shift();
  }
  if (pathParts.length > 1 && pathParts[1] == "test") {
    return "/" + pathParts.slice(0, 2).join("/") + "/";
  }
  // Attempt to detect base url using <base href> html tag
  // base href should start and end with "/"
  if (typeof document !== 'undefined') {
    var el = document.getElementsByTagName('base');
    if (el && el[0] && el[0].getAttribute("href") && el[0].getAttribute
    ("href").startsWith("/") && el[0].getAttribute("href").endsWith("/")){
      return el[0].getAttribute("href");
    }
  }
  // return default value
  return "/";
}());

let modulePaths = {
 "dart_sdk": "packages/build_web_compilers/src/dev_compiler/dart_sdk",
 "packages/collection/collection": "packages/collection/collection.ddc",
 "packages/collection/src/algorithms": "packages/collection/src/algorithms.ddc",
 "packages/collection/src/canonicalized_map": "packages/collection/src/canonicalized_map.ddc",
 "packages/collection/src/comparators": "packages/collection/src/comparators.ddc",
 "packages/collection/src/iterable_zip": "packages/collection/src/iterable_zip.ddc",
 "packages/collection/src/priority_queue": "packages/collection/src/priority_queue.ddc",
 "packages/collection/src/utils": "packages/collection/src/utils.ddc",
 "packages/flutter/animation": "packages/flutter/animation.ddc",
 "packages/flutter/cupertino": "packages/flutter/cupertino.ddc",
 "packages/flutter/foundation": "packages/flutter/foundation.ddc",
 "packages/flutter/gestures": "packages/flutter/gestures.ddc",
 "packages/flutter/material": "packages/flutter/material.ddc",
 "packages/flutter/painting": "packages/flutter/painting.ddc",
 "packages/flutter/physics": "packages/flutter/physics.ddc",
 "packages/flutter/rendering": "packages/flutter/rendering.ddc",
 "packages/flutter/semantics": "packages/flutter/semantics.ddc",
 "packages/flutter/src/animation/animation": "packages/flutter/src/animation/animation.ddc",
 "packages/flutter/src/cupertino/action_sheet": "packages/flutter/src/cupertino/action_sheet.ddc",
 "packages/flutter/src/foundation/_bitfield_web": "packages/flutter/src/foundation/_bitfield_web.ddc",
 "packages/flutter/src/gestures/arena": "packages/flutter/src/gestures/arena.ddc",
 "packages/flutter/src/painting/_network_image_web": "packages/flutter/src/painting/_network_image_web.ddc",
 "packages/flutter/src/physics/clamped_simulation": "packages/flutter/src/physics/clamped_simulation.ddc",
 "packages/flutter/src/rendering/animated_size": "packages/flutter/src/rendering/animated_size.ddc",
 "packages/flutter/src/semantics/binding": "packages/flutter/src/semantics/binding.ddc",
 "packages/flutter/src/widgets/actions": "packages/flutter/src/widgets/actions.ddc",
 "packages/flutter/widgets": "packages/flutter/widgets.ddc",
 "packages/flutter_web_2/main": "packages/flutter_web_2/main.ddc",
 "packages/flutter_web_2/main_web_entrypoint": "packages/flutter_web_2/main_web_entrypoint.ddc",
 "packages/meta/meta": "packages/meta/meta.ddc",
 "packages/typed_data/typed_buffers": "packages/typed_data/typed_buffers.ddc",
 "packages/vector_math/hash": "packages/vector_math/hash.ddc",
 "packages/vector_math/vector_math_64": "packages/vector_math/vector_math_64.ddc"
};
if(!window.$dartLoader) {
   window.$dartLoader = {
     appDigests: _currentDirectory + 'main_web_entrypoint.digests',
     moduleIdToUrl: new Map(),
     urlToModuleId: new Map(),
     rootDirectories: new Array(),
     // Used in package:build_runner/src/server/build_updates_client/hot_reload_client.dart
     moduleParentsGraph: new Map(),
     moduleLoadingErrorCallbacks: new Map(),
     forceLoadModule: function (moduleName, callback, onError) {
       // dartdevc only strips the final extension when adding modules to source
       // maps, so we need to do the same.
       if (moduleName.endsWith('.ddc')) {
         moduleName = moduleName.substring(0, moduleName.length - 4);
       }
       if (typeof onError != 'undefined') {
         var errorCallbacks = $dartLoader.moduleLoadingErrorCallbacks;
         if (!errorCallbacks.has(moduleName)) {
           errorCallbacks.set(moduleName, new Set());
         }
         errorCallbacks.get(moduleName).add(onError);
       }
       requirejs.undef(moduleName);
       requirejs([moduleName], function() {
         if (typeof onError != 'undefined') {
           errorCallbacks.get(moduleName).delete(onError);
         }
         if (typeof callback != 'undefined') {
           callback();
         }
       });
     },
     getModuleLibraries: null, // set up by _initializeTools
   };
}
let customModulePaths = {};
window.$dartLoader.rootDirectories.push(window.location.origin + baseUrl);
for (let moduleName of Object.getOwnPropertyNames(modulePaths)) {
  let modulePath = modulePaths[moduleName];
  if (modulePath != moduleName) {
    customModulePaths[moduleName] = modulePath;
  }
  var src = window.location.origin + '/' + modulePath + '.js';
  if (window.$dartLoader.moduleIdToUrl.has(moduleName)) {
    continue;
  }
  $dartLoader.moduleIdToUrl.set(moduleName, src);
  $dartLoader.urlToModuleId.set(src, moduleName);
}
// Whenever we fail to load a JS module, try to request the corresponding
// `.errors` file, and log it to the console.
(function() {
  var oldOnError = requirejs.onError;
  requirejs.onError = function(e) {
    if (e.requireModules) {
      if (e.message) {
        // If error occurred on loading dependencies, we need to invalidate ancessor too.
        var ancesor = e.message.match(/needed by: (.*)/);
        if (ancesor) {
          e.requireModules.push(ancesor[1]);
        }
      }
      for (const module of e.requireModules) {
        var errorCallbacks = $dartLoader.moduleLoadingErrorCallbacks.get(module);
        if (errorCallbacks) {
          for (const callback of errorCallbacks) callback(e);
          errorCallbacks.clear();
        }
      }
    }
    if (e.originalError && e.originalError.srcElement) {
      var xhr = new XMLHttpRequest();
      xhr.onreadystatechange = function() {
        if (this.readyState == 4) {
          var message;
          if (this.status == 200) {
            message = this.responseText;
          } else {
            message = "Unknown error loading " + e.originalError.srcElement.src;
          }
          console.error(message);
          var errorEvent = new CustomEvent(
            'dartLoadException', { detail: message });
          window.dispatchEvent(errorEvent);
        }
      };
      xhr.open("GET", e.originalError.srcElement.src + ".errors", true);
      xhr.send();
    }
    // Also handle errors the normal way.
    if (oldOnError) oldOnError(e);
  };
}());

var baseUrl = (function () {
  // Attempt to detect --precompiled mode for tests, and set the base url
  // appropriately, otherwise set it to '/'.
  var pathParts = location.pathname.split("/");
  if (pathParts[0] == "") {
    pathParts.shift();
  }
  if (pathParts.length > 1 && pathParts[1] == "test") {
    return "/" + pathParts.slice(0, 2).join("/") + "/";
  }
  // Attempt to detect base url using <base href> html tag
  // base href should start and end with "/"
  if (typeof document !== 'undefined') {
    var el = document.getElementsByTagName('base');
    if (el && el[0] && el[0].getAttribute("href") && el[0].getAttribute
    ("href").startsWith("/") && el[0].getAttribute("href").endsWith("/")){
      return el[0].getAttribute("href");
    }
  }
  // return default value
  return "/";
}());
;

require.config({
    baseUrl: baseUrl,
    waitSeconds: 0,
    paths: customModulePaths
});

const modulesGraph = new Map();
function getRegisteredModuleName(moduleMap) {
  if ($dartLoader.moduleIdToUrl.has(moduleMap.name + '.ddc')) {
    return moduleMap.name + '.ddc';
  }
  return moduleMap.name;
}
requirejs.onResourceLoad = function (context, map, depArray) {
  const name = getRegisteredModuleName(map);
  const depNameArray = depArray.map(getRegisteredModuleName);
  if (modulesGraph.has(name)) {
    // TODO Move this logic to better place
    var previousDeps = modulesGraph.get(name);
    var changed = previousDeps.length != depNameArray.length;
    changed = changed || depNameArray.some(function(depName) {
      return !previousDeps.includes(depName);
    });
    if (changed) {
      console.warn("Dependencies graph change for module '" + name + "' detected. " +
        "Dependencies was [" + previousDeps + "], now [" +  depNameArray.map((depName) => depName) +"]. " +
        "Page can't be hot-reloaded, firing full page reload.");
      window.location.reload();
    }
  } else {
    modulesGraph.set(name, []);
    for (const depName of depNameArray) {
      if (!$dartLoader.moduleParentsGraph.has(depName)) {
        $dartLoader.moduleParentsGraph.set(depName, []);
      }
      $dartLoader.moduleParentsGraph.get(depName).push(name);
      modulesGraph.get(name).push(depName);
    }
  }
};
define("main_web_entrypoint.dart.bootstrap", ["packages/flutter_web_2/main_web_entrypoint", "dart_sdk"], function(app, dart_sdk) {
  dart_sdk.dart.setStartAsyncSynchronously(true);
  dart_sdk._isolate_helper.startRootIsolate(() => {}, []);
  var baseUrl = (function () {
  // Attempt to detect --precompiled mode for tests, and set the base url
  // appropriately, otherwise set it to '/'.
  var pathParts = location.pathname.split("/");
  if (pathParts[0] == "") {
    pathParts.shift();
  }
  if (pathParts.length > 1 && pathParts[1] == "test") {
    return "/" + pathParts.slice(0, 2).join("/") + "/";
  }
  // Attempt to detect base url using <base href> html tag
  // base href should start and end with "/"
  if (typeof document !== 'undefined') {
    var el = document.getElementsByTagName('base');
    if (el && el[0] && el[0].getAttribute("href") && el[0].getAttribute
    ("href").startsWith("/") && el[0].getAttribute("href").endsWith("/")){
      return el[0].getAttribute("href");
    }
  }
  // return default value
  return "/";
}());

  dart_sdk._debugger.registerDevtoolsFormatter();
  $dartLoader.getModuleLibraries = dart_sdk.dart.getModuleLibraries;
  if (window.$dartStackTraceUtility && !window.$dartStackTraceUtility.ready) {
    window.$dartStackTraceUtility.ready = true;
    let dart = dart_sdk.dart;
    window.$dartStackTraceUtility.setSourceMapProvider(
      function(url) {
        url = url.replace(baseUrl, '/');
        var module = window.$dartLoader.urlToModuleId.get(url);
        if (!module) return null;
        return dart.getSourceMap(module);
      });
  }
  if (typeof document != 'undefined') {
    window.postMessage({ type: "DDC_STATE_CHANGE", state: "start" }, "*");
  }
// Injected by webdev for build results support.
window.$dartAppId = "AsveSxf7vMU09lPzqAEX+g==";
window.$dartRunMain = (app.lib__main_web_entrypoint || app.main_web_entrypoint).main;;
window.$dartReloadConfiguration = "ReloadConfiguration.none";
window.$dartLoader.forceLoadModule("dwds/src/injected/client");
window.$dartModuleStrategy = "require";
window.$dartUriBase = "http://localhost:22797";
window.$loadModuleConfig = require;
window.$dartExtensionUri = "http://localhost:22865/$debug";
  var bootstrap = {
      hot$onChildUpdate: function(childName, child) {
        // Special handling for the multi-root scheme uris. We need to strip
        // out the scheme and the top level directory, to match the source path
        // that chrome sees.
        if (childName.startsWith('org-dartlang-app:///')) {
          childName = childName.substring('org-dartlang-app:///'.length);
          var firstSlash = childName.indexOf('/');
          if (firstSlash == -1) return false;
          childName = childName.substring(firstSlash + 1);
        }
        if (childName === "package:flutter_web_2/main_web_entrypoint.dart") {
          // Clear static caches.
          dart_sdk.dart.hotRestart();
          window.$dartRunMain = child.main;
          return true;
        }
      }
    }
  dart_sdk.dart.trackLibraries("main_web_entrypoint.dart.bootstrap", {
    "main_web_entrypoint.dart.bootstrap": bootstrap
  }, '');
  return {
    bootstrap: bootstrap
  };
});
})();