Error: MissingPluginException(No implementation found for method launch on channel plugins.flutter.io/url_launcher) at Object.throw_ [as throw] (http://localhost:53004/dart_sdk.js:5348:11 code example

Example: unhandled exception: missingpluginexception(no implementation found for method launch on channel plugins.flutter.io/url_launcher)

If you are using hot restart or hot reload, it won't do the trick. Since Flutter has to inject plugin dependencies into the platform-specific parts of your app, hot restart/hot reload is not enough to trigger the injection. Check this issue for more.

Close the app and execute flutter run command.