Flutter

Type 'String' is not a subtype of expected type 'int'

Issue

I get this error when searching for results. Spent hours now to debug, but can’t discover what the issue might be. Must be some deserialisation issue, when trying to assign the id to the Place object. But I’m no JavaScript expert (thats why I want to use dart). But of course the files are converted into JavaScript, and the Developer Tools debugger then references to the generated JS files.

The strange thing is that it was working with my mock backend. But it’s not working with the Aqueduct backend. Aqueduct itself is providing the right output.

[{"id":1,"name":"Easyhotel"},{"id":2,"name":"Hotel Greulich"}]

Fetching a list of all objects is working. Seems only to be related to the search method.

Any hint would be appreciated.

Version

Dart VM version: 2.0.0-dev.68.0 (Tue Jul 10 14:47:26 2018 +0200) on “macos_x64”

pubspec.yaml

name: places
description: Cool Places
version: 0.0.1

environment:
  sdk: '>=2.0.0-dev.66.0 <2.0.0'

dependencies:
  angular: ^5.0.0-beta
  angular_forms: ^2.0.0-beta
  angular_router: ^2.0.0-alpha
  http: ^0.11.0            
  stream_transform: ^0.0.6
  angular_components: ^0.9.0-alpha+15

dev_dependencies:
  sass_builder: ^2.0.0
  angular_test: ^2.0.0-beta
  build_runner: ^0.9.0
  build_test: ^0.10.2
  build_web_compilers: ^0.4.0
  test: ^1.0.0

place_search_service.dart

import 'dart:async';
import 'dart:convert';
import 'package:angular/angular.dart';
import 'package:http/http.dart';

import 'package:places/src/place/place.dart';

@Injectable()
class PlaceSearchService {
  final Client _http;

  PlaceSearchService(this._http);

  Future<List<Place>> search(String term) async {
    try {
      final response = await _http.get('http://localhost:8888/places?name=$term');
      return (_extractData(response) as List)
          .map((json) => new Place.fromJson(json))
          .toList();
    } catch (e) {
      throw _handleError(e);
    }
  }

  dynamic _extractData(Response resp) => json.decode(resp.body)['data'];

  Exception _handleError(dynamic e) {
    print(e); // for demo purposes only
    return new Exception('Server error; cause: $e');
  }
}

place.dart

class Place {
  final int id;
  String name;

  Place(this.id, this.name);

  factory Place.fromJson(Map<String, dynamic> place) =>
      new Place(_toInt(place['id']), place['name']);
  Map toJson() => {'id': id, 'name': name};
}

int _toInt(id) => id is int ? id : int.parse(id);

Stacktrace from Chrome Dev Tools

`dart_sdk.js:101652 EXCEPTION: Exception: Server error; cause: Type ‘String’ is not a subtype of expected type ‘int’.
STACKTRACE:
packages/$sdk/dev_compiler/amd/dart_sdk.js 4835:29 throw
packages/places/src/place/place_search_service.ddc.js 28:21 search
packages/$sdk/dev_compiler/amd/dart_sdk.js 23385:33 onValue
packages/stack_trace/stack_trace.ddc.js 142:98 .dart.fn
packages/stack_trace/stack_trace.ddc.js 188:16 [_run]
packages/stack_trace/stack_trace.ddc.js 142:80 arg
packages/angular/src/core/zone/ng_zone.ddc.js 117:18 arg
packages/$sdk/dev_compiler/amd/dart_sdk.js 29365:56 _rootRunUnary
packages/$sdk/dev_compiler/amd/dart_sdk.js 28991:14 runUnary
packages/angular/src/core/zone/ng_zone.ddc.js 114:21 [_runUnary]
packages/$sdk/dev_compiler/amd/dart_sdk.js 29193:14 runUnary
packages/$sdk/dev_compiler/amd/dart_sdk.js 25288:29 handleValue
packages/$sdk/dev_compiler/amd/dart_sdk.js 25750:49 handleValueCallback
packages/$sdk/dev_compiler/amd/dart_sdk.js 25780:17 _propagateToListeners
packages/$sdk/dev_compiler/amd/dart_sdk.js 25643:23 [_completeWithValue]
packages/$sdk/dev_compiler/amd/dart_sdk.js 25661:35 .scheduleMicrotask.dart.fn
packages/angular/src/core/zone/ng_zone.ddc.js 92:11 safeMicrotask
packages/stack_trace/stack_trace.ddc.js 188:16 [_run]
packages/stack_trace/stack_trace.ddc.js 137:71 parent.registerCallback.dart.fn
packages/angular/src/core/zone/ng_zone.ddc.js 107:18 parent.run.dart.fn
packages/$sdk/dev_compiler/amd/dart_sdk.js 29359:14 _rootRun
packages/$sdk/dev_compiler/amd/dart_sdk.js 28985:14 run
packages/angular/src/core/zone/ng_zone.ddc.js 104:21 [_run]
packages/$sdk/dev_compiler/amd/dart_sdk.js 29186:14 run
packages/$sdk/dev_compiler/amd/dart_sdk.js 29106:14 runGuarded
packages/$sdk/dev_compiler/amd/dart_sdk.js 29142:33 async._AsyncCallbackEntry.new.dart.fn
packages/$sdk/dev_compiler/amd/dart_sdk.js 25990:13 _microtaskLoop
packages/$sdk/dev_compiler/amd/dart_sdk.js 25996:13 _startMicrotaskLoop
packages/$sdk/dev_compiler/amd/dart_sdk.js 26066:11 internalCallback

packages/$sdk/dev_compiler/amd/dart_sdk.js 29214:14 registerUnaryCallback
packages/$sdk/dev_compiler/amd/dart_sdk.js 23396:22 async
packages/places/src/place/place_search_service.ddc.js 23:20 search
packages/places/src/place/place_list_component.ddc.js 69:58 search
packages/$sdk/dev_compiler/amd/dart_sdk.js 23404:34 runBody
packages/$sdk/dev_compiler/amd/dart_sdk.js 23431:7 async
packages/places/src/place/place_list_component.ddc.js 65:20 search
packages/places/src/place/place_list_component.template.ddc.js 158:16 [_handle_click_15_0]
packages/angular/src/bootstrap/modules.ddc.js 1869:106 src__core__linker__app_view_utils.appViewUtils.eventManager.getZone.runGuarded.dart.fn
packages/angular/src/core/zone/ng_zone.ddc.js 107:18 parent.run.dart.fn
packages/$sdk/dev_compiler/amd/dart_sdk.js 29359:14 _rootRun
packages/$sdk/dev_compiler/amd/dart_sdk.js 28985:14 run
packages/angular/src/core/zone/ng_zone.ddc.js 104:21 [_run]
packages/$sdk/dev_compiler/amd/dart_sdk.js 29186:14 run
packages/$sdk/dev_compiler/amd/dart_sdk.js 29106:14 runGuarded
packages/angular/src/core/zone/ng_zone.ddc.js 223:31 runGuarded
packages/angular/src/bootstrap/modules.ddc.js 1869:81 event`

When examining the error object by setting a breakpoint

Symbol(_error)
:
Error at Object.dart.throw (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4835:29) at Object.dart.castError (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4462:15) at Object.dart.as (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4751:17) at Function.check_int [as _check] (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:9997:17) at Object.dart._checkApply (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4572:19) at Object.dart._checkAndCall (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4653:14) at Object.dart.callMethod (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4702:17) at Object.dart.dindex (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4717:17) at src__place__place_search_service.PlaceSearchService.new.[_extractData] (http://localhost:8080/packages/places/src/place/place_search_service.ddc.js:33:19) at src__place__place_search_service.PlaceSearchService.new.search (http://localhost:8080/packages/places/src/place/place_search_service.ddc.js:26:49) at search.next (<anonymous>) at onValue (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:23385:33) at (anonymous function).dart.fn (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:142:98) at src__stack_zone_specification.StackZoneSpecification.new.[_run] (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:188:16) at parent.registerUnaryCallback.dart.fn.arg (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:142:80) at parent.runUnary.dart.fn.arg (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:117:18) at async._rootRunUnary (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29365:56) at async._ZoneDelegate.new.runUnary (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:28991:14) at src__core__zone__ng_zone.NgZone.new.[_runUnary] (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:114:21) at async._CustomZone.new.runUnary (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29193:14) at _FutureListener.then.handleValue (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25288:29) at handleValueCallback (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25750:49) at Function._propagateToListeners (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25780:17) at _Future.new.[_completeWithValue] (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25643:23) at (anonymous function).scheduleMicrotask.dart.fn (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25661:35) at safeMicrotask (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:92:11) at src__stack_zone_specification.StackZoneSpecification.new.[_run] (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:188:16) at parent.registerCallback.dart.fn (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:137:71) at parent.run.dart.fn (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:107:18) at async._rootRun (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29359:14) at async._ZoneDelegate.new.run (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:28985:14) at src__core__zone__ng_zone.NgZone.new.[_run] (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:104:21) at async._CustomZone.new.run (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29186:14) at async._CustomZone.new.runGuarded (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29106:14) at async._AsyncCallbackEntry.new.dart.fn [as callback] (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29142:33) at Object.async._microtaskLoop (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25990:13) at async._startMicrotaskLoop (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25996:13) at MutationObserver.internalCallback (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:26066:11)
stack
:
"Error↵ at Object.dart.throw (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4835:29)↵ at Object.dart.castError (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4462:15)↵ at Object.dart.as (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4751:17)↵ at Function.check_int [as _check] (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:9997:17)↵ at Object.dart._checkApply (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4572:19)↵ at Object.dart._checkAndCall (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4653:14)↵ at Object.dart.callMethod (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4702:17)↵ at Object.dart.dindex (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:4717:17)↵ at src__place__place_search_service.PlaceSearchService.new.[_extractData] (http://localhost:8080/packages/places/src/place/place_search_service.ddc.js:33:19)↵ at src__place__place_search_service.PlaceSearchService.new.search (http://localhost:8080/packages/places/src/place/place_search_service.ddc.js:26:49)↵ at search.next (<anonymous>)↵ at onValue (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:23385:33)↵ at (anonymous function).dart.fn (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:142:98)↵ at src__stack_zone_specification.StackZoneSpecification.new.[_run] (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:188:16)↵ at parent.registerUnaryCallback.dart.fn.arg (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:142:80)↵ at parent.runUnary.dart.fn.arg (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:117:18)↵ at async._rootRunUnary (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29365:56)↵ at async._ZoneDelegate.new.runUnary (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:28991:14)↵ at src__core__zone__ng_zone.NgZone.new.[_runUnary] (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:114:21)↵ at async._CustomZone.new.runUnary (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29193:14)↵ at _FutureListener.then.handleValue (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25288:29)↵ at handleValueCallback (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25750:49)↵ at Function._propagateToListeners (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25780:17)↵ at _Future.new.[_completeWithValue] (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25643:23)↵ at (anonymous function).scheduleMicrotask.dart.fn (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25661:35)↵ at safeMicrotask (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:92:11)↵ at src__stack_zone_specification.StackZoneSpecification.new.[_run] (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:188:16)↵ at parent.registerCallback.dart.fn (http://localhost:8080/packages/stack_trace/stack_trace.ddc.js:137:71)↵ at parent.run.dart.fn (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:107:18)↵ at async._rootRun (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29359:14)↵ at async._ZoneDelegate.new.run (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:28985:14)↵ at src__core__zone__ng_zone.NgZone.new.[_run] (http://localhost:8080/packages/angular/src/core/zone/ng_zone.ddc.js:104:21)↵ at async._CustomZone.new.run (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29186:14)↵ at async._CustomZone.new.runGuarded (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29106:14)↵ at async._AsyncCallbackEntry.new.dart.fn [as callback] (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:29142:33)↵ at Object.async._microtaskLoop (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25990:13)↵ at async._startMicrotaskLoop (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:25996:13)↵ at MutationObserver.internalCallback (http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js:26066:11)"

With commented out throw _handleError

`dart_sdk.js:101652 EXCEPTION: TypeError: Cannot read property ‘Symbol(dartx.length)’ of undefined
STACKTRACE:
packages/places/src/place/place_list_component.ddc.js 71:24 search
packages/$sdk/dev_compiler/amd/dart_sdk.js 23385:33 onValue
packages/stack_trace/stack_trace.ddc.js 142:98 .dart.fn
packages/stack_trace/stack_trace.ddc.js 188:16 [_run]
packages/stack_trace/stack_trace.ddc.js 142:80 arg
packages/angular/src/core/zone/ng_zone.ddc.js 117:18 arg
packages/$sdk/dev_compiler/amd/dart_sdk.js 29365:56 _rootRunUnary
packages/$sdk/dev_compiler/amd/dart_sdk.js 28991:14 runUnary
packages/angular/src/core/zone/ng_zone.ddc.js 114:21 [_runUnary]
packages/$sdk/dev_compiler/amd/dart_sdk.js 29193:14 runUnary
packages/$sdk/dev_compiler/amd/dart_sdk.js 25288:29 handleValue
packages/$sdk/dev_compiler/amd/dart_sdk.js 25750:49 handleValueCallback
packages/$sdk/dev_compiler/amd/dart_sdk.js 25780:17 _propagateToListeners
packages/$sdk/dev_compiler/amd/dart_sdk.js 25643:23 [_completeWithValue]
packages/$sdk/dev_compiler/amd/dart_sdk.js 25661:35 .scheduleMicrotask.dart.fn
packages/angular/src/core/zone/ng_zone.ddc.js 92:11 safeMicrotask
packages/stack_trace/stack_trace.ddc.js 188:16 [_run]
packages/stack_trace/stack_trace.ddc.js 137:71 parent.registerCallback.dart.fn
packages/angular/src/core/zone/ng_zone.ddc.js 107:18 parent.run.dart.fn
packages/$sdk/dev_compiler/amd/dart_sdk.js 29359:14 _rootRun
packages/$sdk/dev_compiler/amd/dart_sdk.js 28985:14 run
packages/angular/src/core/zone/ng_zone.ddc.js 104:21 [_run]
packages/$sdk/dev_compiler/amd/dart_sdk.js 29186:14 run
packages/$sdk/dev_compiler/amd/dart_sdk.js 29106:14 runGuarded
packages/$sdk/dev_compiler/amd/dart_sdk.js 29142:33 async._AsyncCallbackEntry.new.dart.fn
packages/$sdk/dev_compiler/amd/dart_sdk.js 25990:13 _microtaskLoop
packages/$sdk/dev_compiler/amd/dart_sdk.js 25996:13 _startMicrotaskLoop
packages/$sdk/dev_compiler/amd/dart_sdk.js 26066:11 internalCallback

packages/$sdk/dev_compiler/amd/dart_sdk.js 29214:14 registerUnaryCallback
packages/$sdk/dev_compiler/amd/dart_sdk.js 23396:22 async
packages/places/src/place/place_list_component.ddc.js 65:20 search
packages/places/src/place/place_list_component.template.ddc.js 158:16 [_handle_click_15_0]
packages/angular/src/bootstrap/modules.ddc.js 1869:106 src__core__linker__app_view_utils.appViewUtils.eventManager.getZone.runGuarded.dart.fn
packages/angular/src/core/zone/ng_zone.ddc.js 107:18 parent.run.dart.fn
packages/$sdk/dev_compiler/amd/dart_sdk.js 29359:14 _rootRun
packages/$sdk/dev_compiler/amd/dart_sdk.js 28985:14 run
packages/angular/src/core/zone/ng_zone.ddc.js 104:21 [_run]
packages/$sdk/dev_compiler/amd/dart_sdk.js 29186:14 run
packages/$sdk/dev_compiler/amd/dart_sdk.js 29106:14 runGuarded
packages/angular/src/core/zone/ng_zone.ddc.js 223:31 runGuarded
packages/angular/src/bootstrap/modules.ddc.js 1869:81 event

error @ dart_sdk.js:101652
handle @ exceptions.dart:14
call @ exceptions.dart:11
handleUncaughtException @ application_ref.dart:134
(anonymous function).(anonymous function).(anonymous function).onError.listen.dart.fn.error @ application_ref.dart:51
(anonymous function).dart.fn @ stack_zone_specification.dart:129
[_run] @ stack_zone_specification.dart:209
parent.registerUnaryCallback.dart.fn.arg @ stack_zone_specification.dart:129
parent.runUnary.dart.fn.arg @ ng_zone.dart:190
async._rootRunUnary @ dart_sdk.js:29368
runUnary @ dart_sdk.js:28991
[_runUnary] @ ng_zone.dart:187
runUnary @ dart_sdk.js:29193
runUnaryGuarded @ dart_sdk.js:29114
[_sendData] @ dart_sdk.js:23973
[_add] @ dart_sdk.js:23920
[_sendData] @ dart_sdk.js:24605
add @ dart_sdk.js:24415
[_onErrorWithLongStackTrace] @ ng_zone.dart:228
async._rootRunBinary @ dart_sdk.js:29377
runBinary @ dart_sdk.js:29579
[_handleUncaughtError] @ stack_zone_specification.dart:163
handleUncaughtError @ dart_sdk.js:29170
_propagateToListeners @ dart_sdk.js:25693
[_completeWithValue] @ dart_sdk.js:25643
(anonymous function).scheduleMicrotask.dart.fn @ dart_sdk.js:25661
safeMicrotask @ ng_zone.dart:163
[_run] @ stack_zone_specification.dart:209
parent.registerCallback.dart.fn @ stack_zone_specification.dart:119
parent.run.dart.fn @ ng_zone.dart:178
async._rootRun @ dart_sdk.js:29359
run @ dart_sdk.js:28985
[_run] @ ng_zone.dart:175
run @ dart_sdk.js:29186
runGuarded @ dart_sdk.js:29106
dart.fn @ dart_sdk.js:29142
async._microtaskLoop @ dart_sdk.js:25990
async._startMicrotaskLoop @ dart_sdk.js:25996
internalCallback @ dart_sdk.js:26066
childList (async)
dart.fn.callback @ dart_sdk.js:26076
_scheduleImmediate @ dart_sdk.js:26052
async._scheduleAsyncCallback @ dart_sdk.js:26010
async._rootScheduleMicrotask @ dart_sdk.js:29404
scheduleMicrotask @ dart_sdk.js:29028
[_scheduleMicrotask] @ ng_zone.dart:171
scheduleMicrotask @ dart_sdk.js:29237
[_asyncComplete] @ dart_sdk.js:25660
complete @ dart_sdk.js:25194
reader.(anonymous function).first.then.dart.fn._ @ browser_client.dart:60
(anonymous function).dart.fn @ stack_zone_specification.dart:129
[_run] @ stack_zone_specification.dart:209
parent.registerUnaryCallback.dart.fn.arg @ stack_zone_specification.dart:129
parent.runUnary.dart.fn.arg @ ng_zone.dart:190
async._rootRunUnary @ dart_sdk.js:29365
runUnary @ dart_sdk.js:28991
[_runUnary] @ ng_zone.dart:187
runUnary @ dart_sdk.js:29193
handleValue @ dart_sdk.js:25288
handleValueCallback @ dart_sdk.js:25750
_propagateToListeners @ dart_sdk.js:25780
[_complete] @ dart_sdk.js:25634
async._cancelAndValue @ dart_sdk.js:27687
subscription.listen.dart.fn.value @ dart_sdk.js:10492
dart._checkAndCall @ dart_sdk.js:4656
dart.dcall @ dart_sdk.js:4661
(anonymous function).html$._wrapZone.dart.fn.e @ dart_sdk.js:99172
(anonymous function).dart.fn @ stack_zone_specification.dart:129
[_run] @ stack_zone_specification.dart:209
parent.registerUnaryCallback.dart.fn.arg @ stack_zone_specification.dart:129
parent.runUnary.dart.fn.arg @ ng_zone.dart:190
async._rootRunUnary @ dart_sdk.js:29368
runUnary @ dart_sdk.js:28991
[_runUnary] @ ng_zone.dart:187
runUnary @ dart_sdk.js:29193
runUnaryGuarded @ dart_sdk.js:29114
dart.fn.arg @ dart_sdk.js:29146
load (async)
[_addEventListener] @ dart_sdk.js:57186
[dartx.addEventListener] @ dart_sdk.js:57176
[_tryResume] @ dart_sdk.js:99153
_EventStreamSubscription.new @ dart_sdk.js:99173
listen @ dart_sdk.js:98974
get first @ dart_sdk.js:10491
async.async.xhr.(anonymous function).first.then.dart.fn._ @ browser_client.dart:58
(anonymous function).dart.fn @ stack_zone_specification.dart:129
[_run] @ stack_zone_specification.dart:209
parent.registerUnaryCallback.dart.fn.arg @ stack_zone_specification.dart:129
parent.runUnary.dart.fn.arg @ ng_zone.dart:190
async._rootRunUnary @ dart_sdk.js:29365
runUnary @ dart_sdk.js:28991
[_runUnary] @ ng_zone.dart:187
runUnary @ dart_sdk.js:29193
handleValue @ dart_sdk.js:25288
handleValueCallback @ dart_sdk.js:25750
_propagateToListeners @ dart_sdk.js:25780
[_complete] @ dart_sdk.js:25634
async._cancelAndValue @ dart_sdk.js:27687
subscription.listen.dart.fn.value @ dart_sdk.js:10492
dart._checkAndCall @ dart_sdk.js:4656
dart.dcall @ dart_sdk.js:4661
(anonymous function).html$._wrapZone.dart.fn.e @ dart_sdk.js:99172
(anonymous function).dart.fn @ stack_zone_specification.dart:129
[_run] @ stack_zone_specification.dart:209
parent.registerUnaryCallback.dart.fn.arg @ stack_zone_specification.dart:129
parent.runUnary.dart.fn.arg @ ng_zone.dart:190
async._rootRunUnary @ dart_sdk.js:29368
runUnary @ dart_sdk.js:28991
[_runUnary] @ ng_zone.dart:187
runUnary @ dart_sdk.js:29193
runUnaryGuarded @ dart_sdk.js:29114
dart.fn.arg @ dart_sdk.js:29146
load (async)
[_addEventListener] @ dart_sdk.js:57186
[dartx.addEventListener] @ dart_sdk.js:57176
[_tryResume] @ dart_sdk.js:99153
_EventStreamSubscription.new @ dart_sdk.js:99173
listen @ dart_sdk.js:98974
get first @ dart_sdk.js:10491
send @ browser_client.dart:52
onValue @ dart_sdk.js:23385
(anonymous function).dart.fn @ stack_zone_specification.dart:129
[_run] @ stack_zone_specification.dart:209
parent.registerUnaryCallback.dart.fn.arg @ stack_zone_specification.dart:129
parent.runUnary.dart.fn.arg @ ng_zone.dart:190
async._rootRunUnary @ dart_sdk.js:29365
runUnary @ dart_sdk.js:28991
[_runUnary] @ ng_zone.dart:187
runUnary @ dart_sdk.js:29193
handleValue @ dart_sdk.js:25288
handleValueCallback @ dart_sdk.js:25750
_propagateToListeners @ dart_sdk.js:25780
[_completeWithValue] @ dart_sdk.js:25643
(anonymous function).scheduleMicrotask.dart.fn @ dart_sdk.js:25661
safeMicrotask @ ng_zone.dart:163
[_run] @ stack_zone_specification.dart:209
parent.registerCallback.dart.fn @ stack_zone_specification.dart:119
parent.run.dart.fn @ ng_zone.dart:178
async._rootRun @ dart_sdk.js:29359
run @ dart_sdk.js:28985
[_run] @ ng_zone.dart:175
run @ dart_sdk.js:29186
runGuarded @ dart_sdk.js:29106
dart.fn @ dart_sdk.js:29142
async._microtaskLoop @ dart_sdk.js:25990
async._startMicrotaskLoop @ dart_sdk.js:25996
internalCallback @ dart_sdk.js:26066
childList (async)
dart.fn.callback @ dart_sdk.js:26076
_scheduleImmediate @ dart_sdk.js:26052
async._scheduleAsyncCallback @ dart_sdk.js:26010
async._rootScheduleMicrotask @ dart_sdk.js:29404
scheduleMicrotask @ dart_sdk.js:29028
[_scheduleMicrotask] @ ng_zone.dart:171
scheduleMicrotask @ dart_sdk.js:29237
async.scheduleMicrotask @ dart_sdk.js:26048
schedule @ dart_sdk.js:26968
[_setPendingEvents] @ dart_sdk.js:23798
[_createSubscription] @ dart_sdk.js:26927
listen @ dart_sdk.js:23656
listen @ dart_sdk.js:26156
toBytes @ byte_stream.dart:24
send @ browser_client.dart:43
runBody @ dart_sdk.js:23404
async.async @ dart_sdk.js:23431
send @ browser_client.dart:42
_sendUnstreamed @ base_client.dart:171
runBody @ dart_sdk.js:23404
async.async @ dart_sdk.js:23431
[_sendUnstreamed] @ base_client.dart:152
get @ base_client.dart:34
search @ place_search_service.dart:16
runBody @ dart_sdk.js:23404
async.async @ dart_sdk.js:23431
search @ place_search_service.dart:14
search @ place_list_component.dart:54
runBody @ dart_sdk.js:23404
async.async @ dart_sdk.js:23431
search @ place_list_component.dart:50
[_handle_click_15_0] @ place_list_component.template.dart:160
src__core__linker__app_view_utils.appViewUtils.eventManager.getZone.runGuarded.dart.fn @ app_view.dart:619
parent.run.dart.fn @ ng_zone.dart:178
async._rootRun @ dart_sdk.js:29359
run @ dart_sdk.js:28985
[_run] @ ng_zone.dart:175
run @ dart_sdk.js:29186
runGuarded @ dart_sdk.js:29106
runGuarded @ ng_zone.dart:333
dart.fn.event`

Solution

Found the error. Actually in the Mock interface, it was:

dynamic _extractData(Response resp) => json.decode(resp.body)[data];

But in the Aqueduct interface the response is not enclosed in a JSON “data” tag. So changing it to 

dynamic _extractData(Response resp) => json.decode(resp.body);

solved my problem.

So when getting an error such as:

TypeError: Cannot read property ‘Symbol(dartx.length)’ of undefined

it most likely means, that the response might not contain the correct json.

Answered By – Christopher Armstrong

Answer Checked By – Terry (FlutterFixes Volunteer)

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