added null safety

Author: ritvij14

lib/src/EnhancedEventEmitter.dart

@@ -8,7 +8,7 @@ Logger _logger = Logger('EnhancedEventEmitter');
 
 class EnhancedEventEmitter extends EventEmitter {
   EnhancedEventEmitter() : super();
-  void safeEmit(String event, [Map<String, dynamic> args]) {
+  void safeEmit(String event, [Map<String, dynamic>? args]) {
     try {
       emit(event, args);
     } catch (error) {
@@ -19,7 +19,7 @@ class EnhancedEventEmitter extends EventEmitter {
   }
 
   Future<dynamic> safeEmitAsFuture(String event,
-      [Map<String, dynamic> args]) async {
+      [Map<String, dynamic>? args]) async {
     try {
       return emitAsFuture(event, args);
     } catch (error) {

lib/src/message.dart

@@ -8,7 +8,7 @@ final logger = new Logger('Message');
 class Message {
   static JsonEncoder encoder = new JsonEncoder();
   static JsonDecoder decoder = new JsonDecoder();
-  static Map<String, dynamic> parse(dynamic raw) {
+  static Map<String, dynamic>? parse(dynamic raw) {
     var object;
     final message = Map<String, dynamic>();
 

lib/src/peer.dart

@@ -23,7 +23,7 @@ class Peer extends EnhancedEventEmitter {
   var _sents = Map<String, dynamic>();
 
   // Transport.
-  TransportInterface _transport;
+  late TransportInterface _transport;
 
   Peer(TransportInterface transport) {
     _transport = transport;

lib/src/transports/NativeTransport.dart

@@ -8,13 +8,12 @@ import 'TransportInterface.dart';
 final _logger = Logger('Logger::NativeTransport');
 
 class Transport extends TransportInterface {
-  bool _closed;
-  String _url;
-  dynamic _options;
-  WebSocket _ws;
+  late bool _closed;
+  late String _url;
+  late dynamic _options;
+  WebSocket? _ws;
 
-  Transport(String url, {dynamic options})
-      : super(url, options: options) {
+  Transport(String url, {dynamic options}) : super(url, options: options) {
     _logger.debug('constructor() [url:$url, options:$options]');
     this._closed = false;
     this._url = url;
@@ -34,7 +33,7 @@ class Transport extends TransportInterface {
     this.safeEmit('close');
 
     try {
-      this._ws.close();
+      this._ws?.close();
     } catch (error) {
       _logger.error('close() | error closing the WebSocket: $error');
     }
@@ -43,7 +42,7 @@ class Transport extends TransportInterface {
   @override
   Future send(message) async {
     try {
-      this._ws.add(jsonEncode(message));
+      this._ws?.add(jsonEncode(message));
     } catch (error) {
       _logger.warn('send() failed:$error');
     }
@@ -68,7 +67,7 @@ class Transport extends TransportInterface {
 
   _runWebSocket() async {
     WebSocket.connect(this._url, protocols: ['protoo']).then((ws) {
-      if (ws?.readyState == WebSocket.open) {
+      if (ws.readyState == WebSocket.open) {
         this._ws = ws;
         _onOpen();
 

lib/src/transports/WebTransport.dart

@@ -8,10 +8,10 @@ import 'TransportInterface.dart';
 final _logger = Logger('Logger::WebTransport');
 
 class Transport extends TransportInterface {
-  bool _closed;
-  String _url;
-  dynamic _options;
-  WebSocket _ws;
+  late bool _closed;
+  late String _url;
+  late dynamic _options;
+  WebSocket? _ws;
 
   Transport(String url, {dynamic options}) : super(url, options: options) {
     _logger.debug('constructor() [url:$url, options:$options]');
@@ -33,7 +33,7 @@ class Transport extends TransportInterface {
     this.safeEmit('close');
 
     try {
-      this._ws.close();
+      this._ws?.close();
     } catch (error) {
       _logger.error('close() | error closing the WebSocket: $error');
     }
@@ -42,32 +42,32 @@ class Transport extends TransportInterface {
   @override
   Future send(message) async {
     try {
-      this._ws.send(jsonEncode(message));
+      this._ws?.send(jsonEncode(message));
     } catch (error) {
       _logger.warn('send() failed:$error');
     }
   }
 
   _runWebSocket() {
     this._ws = new WebSocket(this._url, 'protoo');
-    this._ws.onOpen.listen((e) {
+    this._ws?.onOpen.listen((e) {
       _logger.debug('onOpen');
       this.safeEmit('open');
     });
 
-    this._ws.onClose.listen((e) {
+    this._ws?.onClose.listen((e) {
       _logger.warn(
           'WebSocket "close" event [wasClean:${e.wasClean}, code:${e.code}, reason:"${e.reason}"]');
       this._closed = true;
 
       this.safeEmit('close');
     });
 
-    this._ws.onError.listen((e) {
+    this._ws?.onError.listen((e) {
       _logger.error('WebSocket "error" event');
     });
 
-    this._ws.onMessage.listen((e) {
+    this._ws?.onMessage.listen((e) {
       final message = Message.parse(e.data);
 
       if (message == null) return;

pubspec.yaml

@@ -3,7 +3,7 @@ version: 0.3.0
 description: Dart version of the protoo-client library.
 homepage: https://github.com/cloudwebrtc/dart-protoo-client
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   events2: ^1.0.0