javascriptChannels: <JavascriptChannel>[
                  JavascriptChannel(
                    name: 'xxBridge',
                    onMessageReceived: (JavascriptMessage jsMessage) {
                      Map messageMap = json.decode(jsMessage.message);
                      print(messageMap);
                      if (messageMap['type'] == 'appPagePop') {
                        Navigator.pop(context, messageMap['value']);
                        return;
                      }
                      if (messageMap['type'] == 'navigateTo') {
                        Map params = messageMap['params'];
                        String patientCode = params['code'];
                        Routes.navigateTo(context, messageMap['url'],
                            params: {'id': UserUtil.transferCodeToId(patientCode)});
                        return;
                      }
                    },
                  ),
                ].toSet()

export default class xxBridge {
  isApp: boolean;
  constructor() {
    /**
     *  receipt app  message callback func
     * @param message
     * @returns boolean
     */
    window.flutterMessage = (message: string) => {
      console.log(message, ' receipt app message');
      return true;
    };
  }
  appPagePop = (value = false) => {
    if (!this.isApp) {
      console.log('當(dāng)前不是app環(huán)境，或者沒(méi)有Bridge 運(yùn)行時(shí)哦 ~ ！');
      window.history.back();
      return;
    }
    window.xxBridge.postMessage(
      JSON.stringify({
        type: 'appPagePop',
        value: value,
      }),
    );
  };
}

onPageFinished: (url) {
                  print(url + '加載完成');
                  Map data = {
                    'doctorCode': UserUtil.doctorCode(),
                    'doctorName': SpUtil.getString(DOCTOR_NAME_KEY),
                  };
                  var dataJson = json.encode(data);
                  print(dataJson);
                  _webviewController?.evaluateJavascript("getAppLoginInfo('$dataJson')").then((res) {
                    print("evaluateJavascript-res: ${res}"); // evaluateJavascript-res: true
                  });
                  // print('加載結(jié)束');
                },

function print(msg) {
  return new Promise((resolve, reject) => {
     resolve('code : xxxxx')
    alert(msg)
  });
}

import 'dart:js' as js;
@JS()
external print(String msg);
var wxScanPromise = print('123');
String code = await jsUtil.promiseToFuture(wxScanPromise)

class Application {
  static Future init(ui.VoidCallback callback) async {
    DarttoJS().into();
  }
  ...
}

//  This's a test dart to js func
class DarttoJS {
  // js call dart
  static void myalert(String text) {
    Fluttertoast.showToast(
        msg: "This's JS pass on test ?。?text",
        toastLength: Toast.LENGTH_SHORT,
        gravity: ToastGravity.CENTER,
        timeInSecForIosWeb: 1,
        backgroundColor: Colors.red,
        textColor: Colors.white,
        fontSize: 16.0);
  }
  void into() {
    js.context["myalert"] = myalert;
    js.context.callMethod('onLogin');
  }
}

const onLogin = () => {
    ...
}
export { onLogin }