Removed dynamic load of js libraries, added web setup to README.md

@@ -53,6 +53,12 @@ Ensure that you granted camera permission in XCode -> Signing & Capabilities:
 
 <img width="696" alt="Screenshot of XCode where Camera is checked" src="https://user-images.githubusercontent.com/24459435/193464115-d76f81d0-6355-4cb2-8bee-538e413a3ad0.png">
 
+## Web
+This package uses ZXing on web to read barcodes so it needs to be included in `index.html` as script.
+```html
+<script src="https://unpkg.com/@zxing/library@0.19.1" type="application/javascript"/>
+```
+
 ## Usage
 
 Import `package:mobile_scanner/mobile_scanner.dart`, and use the widget with or without the controller.

@@ -8,7 +8,6 @@ import 'package:mobile_scanner/mobile_scanner_web.dart';
 import 'package:mobile_scanner/src/barcode_utility.dart';
 import 'package:mobile_scanner/src/enums/camera_facing.dart';
 import 'package:mobile_scanner/src/objects/barcode.dart';
-import 'package:mobile_scanner/src/web/utils.dart';
 
 /// This plugin is the web implementation of mobile_scanner.
 /// It only supports QR codes.
@@ -26,8 +25,6 @@ class MobileScannerWebPlugin {
     );
     final MobileScannerWebPlugin instance = MobileScannerWebPlugin();
 
-    _jsLibrariesLoadingFuture = injectJSLibraries(barCodeReader.jsLibraries);
-
     channel.setMethodCallHandler(instance.handleMethodCall);
     event.setController(instance.controller);
   }
@@ -55,11 +52,8 @@ class MobileScannerWebPlugin {
       ZXingBarcodeReader(videoContainer: vidDiv);
   StreamSubscription? _barCodeStreamSubscription;
 
-  static late Future _jsLibrariesLoadingFuture;
-
   /// Handle incomming messages
   Future<dynamic> handleMethodCall(MethodCall call) async {
-    await _jsLibrariesLoadingFuture;
     switch (call.method) {
       case 'start':
         return _start(call.arguments as Map);

@@ -39,9 +39,6 @@ abstract class WebBarcodeReaderBase {
   int get videoWidth;
   int get videoHeight;
 
-  /// JS libraries to be injected into html page.
-  List<JsLibrary> get jsLibraries;
-
   /// Starts streaming video
   Future<void> start({
     required CameraFacing cameraFacing,

@@ -20,12 +20,6 @@ class Code {
   external Uint8ClampedList get binaryData;
 }
 
-const jsqrLibrary = JsLibrary(
-  contextName: 'jsQR',
-  url: 'https://cdn.jsdelivr.net/npm/jsqr@1.4.0/dist/jsQR.min.js',
-  usesRequireJs: true,
-);
-
 /// Barcode reader that uses jsQR library.
 /// jsQR supports only QR codes format.
 class JsQrCodeReader extends WebBarcodeReaderBase
@@ -36,9 +30,6 @@ class JsQrCodeReader extends WebBarcodeReaderBase
   bool get isStarted => localMediaStream != null;
 
   @override
-  List<JsLibrary> get jsLibraries => [jsqrLibrary];
-
-  @override
   Future<void> start({
     required CameraFacing cameraFacing,
     List<BarcodeFormat>? formats,

-import 'dart:async';
-import 'dart:html' as html;
-import 'dart:js' show JsObject, context;
-
-import 'package:mobile_scanner/src/web/base.dart';
-
-Future<void> loadScript(JsLibrary library) async {
-  dynamic amd;
-  dynamic define;
-  // ignore: avoid_dynamic_calls
-  if (library.usesRequireJs && context['define']?['amd'] != null) {
-    // In dev, requireJs is loaded in. Disable it here.
-    // see https://github.com/dart-lang/sdk/issues/33979
-    define = JsObject.fromBrowserObject(context['define'] as Object);
-    // ignore: avoid_dynamic_calls
-    amd = define['amd'];
-    // ignore: avoid_dynamic_calls
-    define['amd'] = false;
-  }
-  try {
-    await loadScriptUsingScriptTag(library.url);
-  } finally {
-    if (amd != null) {
-      // Re-enable requireJs
-      // ignore: avoid_dynamic_calls
-      define['amd'] = amd;
-    }
-  }
-}
-
-Future<void> loadScriptUsingScriptTag(String url) {
-  final script = html.ScriptElement()
-    ..async = true
-    ..defer = false
-    ..crossOrigin = 'anonymous'
-    ..type = 'text/javascript'
-    // ignore: unsafe_html
-    ..src = url;
-
-  html.document.head!.append(script);
-
-  return script.onLoad.first;
-}
-
-/// Injects JS [libraries]
-///
-/// Returns a [Future] that resolves when all of the `script` tags `onLoad` events trigger.
-Future<void> injectJSLibraries(List<JsLibrary> libraries) {
-  final List<Future<void>> loading = [];
-
-  for (final library in libraries) {
-    final future = loadScript(library);
-    loading.add(future);
-  }
-
-  return Future.wait(loading);
-}

@@ -168,12 +168,6 @@ extension JsZXingBrowserMultiFormatReaderExt
   external MediaStream? stream;
 }
 
-const zxingJsLibrary = JsLibrary(
-  contextName: 'ZXing',
-  url: 'https://unpkg.com/@zxing/library@0.19.1',
-  usesRequireJs: true,
-);
-
 /// Barcode reader that uses zxing-js library.
 class ZXingBarcodeReader extends WebBarcodeReaderBase
     with InternalStreamCreation, InternalTorchDetection {
@@ -185,9 +179,6 @@ class ZXingBarcodeReader extends WebBarcodeReaderBase
   bool get isStarted => localMediaStream != null;
 
   @override
-  List<JsLibrary> get jsLibraries => [zxingJsLibrary];
-
-  @override
   Future<void> start({
     required CameraFacing cameraFacing,
     List<BarcodeFormat>? formats,