TypeError:您在需要流的地方提供了“undefined”。您可以提供一个可观察的、promise的、数组的或可迭代的。在

Question

嗨，我在ngonit中添加了这段代码，用于轮询，添加后，我所有的测试用例都失败了。请帮助如何解决？

  ngOnInit(): void {
this.timeInterval = interval(5000)
.pipe(
  startWith(0),
  switchMap(() => this.deviceService.getDeviceList())
)
.pipe(
  takeUntil(this.deviceService.flag$),
  repeatWhen(() => this.deviceService.flag$)
)
.subscribe((success: any) => {
  this.gridApi?.setRowData(this.updatedData);
  console.log("hello")
  this.updatedData = success;
}, retry(2));

这是完全的错误

HeadlessChrome 88.0.4324 (Windows 10.0.0) DeviceComponent testing columnresize of the grid for other scenario FAILED
    TypeError: You provided 'undefined' where a stream was expected. You can provide an Observable, Promise, Array, or Iterable.
        at <Jasmine>
        at subscribeTo (http://localhost:9876/_karma_webpack_/node_modules/rxjs/_esm2015/internal/util/subscribeTo.js:27:1)
        at innerSubscribe (http://localhost:9876/_karma_webpack_/node_modules/rxjs/_esm2015/internal/innerSubscribe.js:69:23)
        at TakeUntilOperator.call (http://localhost:9876/_karma_webpack_/node_modules/rxjs/_esm2015/internal/operators/takeUntil.js:11:52)
        at Observable.subscribe (http://localhost:9876/_karma_webpack_/node_modules/rxjs/_esm2015/internal/Observable.js:23:1)
        at RepeatWhenOperator.call (http://localhost:9876/_karma_webpack_/node_modules/rxjs/_esm2015/internal/operators/repeatWhen.js:11:1)
        at Observable.subscribe (http://localhost:9876/_karma_webpack_/node_modules/rxjs/_esm2015/internal/Observable.js:23:1)
        at DeviceComponent.ngOnInit (http://localhost:9876/_karma_webpack_/src/app/device/device.component.ts:99:4)
        at callHook (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:3937:1)
        at callHooks (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:3901:1)
        at executeInitAndCheckHooks (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:3842:1)
    Failed: Cannot read property 'unsubscribe' of undefined
        at <Jasmine>
        at DeviceComponent.ngOnDestroy (http://localhost:9876/_karma_webpack_/main.js:28373:23)
        at UserContext.<anonymous> (http://localhost:9876/_karma_webpack_/src/app/device/device.component.spec.ts:196:15)
        at ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:365:1)
        at AsyncTestZoneSpec.onInvoke (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-testing.js:763:1)
        at ProxyZoneSpec.onInvoke (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-testing.js:302:1)
        at ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:364:1)
        at Zone.runGuarded (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:134:1)
        at runInTestZone (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-testing.js:885:1)
        at UserContext.<anonymous> (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-testing.js:823:1)
        at ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:365:1)

HeadlessChrome 88.04324（Windows 10.0.0）：已执行第1个，共385个（1个失败）（0秒/1.732秒）HeadlessChrome 880.4324（Windows 10.00）DeviceComponent测试其他场景的网格列大小失败类型错误：您在预期流的位置提供了“未定义”。您可以提供Observable、Promise、Array或Iterable。位于subscribeTo(http://localhost:9876/karma_webpack/node_modules/rxjs/_esm2015/internal/util/subscribeTo.js:27:1)位于innerSubscribe(http://localhost:9876/karma_webpack/node_modules/rxjs/_esm2015/internal/innerSubscribe.js:69:23)在TakeUntilOperator。呼叫(http://localhost:9876/karma_webpack/node_modules/rxjs/_esm2015/internal/operators/takeUntil.js:11:52)在Observable。订阅(http://localhost:9876/karma_webpack/node_modules/rxjs/_esm2015/internal/Observable.js:23:1)在RepeatWhenOperator。呼叫(http://localhost:9876/karma_webpack/node_modules/rxjs/_esm2015/internal/operators/repeatWhen.js:11:1)在Observable。订阅(http://localhost:9876/karma_webpack/node_modules/rxjs/_esm2015/internal/Observable.js:23:1)位于DeviceComponent。ng初始(http://localhost:9876/karma_webpack/src/app/device/device.component.ts:99:4)在callHook(http://localhost:9876/karma_webpack/node_modules/@angular/core/ivy_ngcc/fesm2015/core。js:3937:1）在callHooks(http://localhost:9876/karma_webpack/node_modules/@angular/core/ivy_ngcc/fesm2015/core。js:3901:1）在executeInitAndCheckHooks(http://localhost:9876/karma_webpack/node_modules/@angular/core/ivy_ngcc/fesm2015/core。js:3842:1）失败：无法读取DeviceComponent处未定义的属性“unsubscribe”。ng销毁(http://localhost:9876/karma_webpack/main.js:28373:23)在UserContext上。(http://localhost:9876/karma_webpack/src/app/device/device.component.spec.ts:196:15)ZoneDelegate。调用(http://localhost:9876/karma_webpack/node_modules/zone.js/dist/zone-常青树.js:365:1）

Answer 1

我有一个类似的问题。

我建议检查这些方法是否在您的 2 个 switchMap 运算符调用中返回可观察量：

this.deviceService.getDeviceList()
this.deviceService.flag$

这就是我的原因。switchMap运算符必须返回一个可观察值。所以可能发生的情况是，在你的代码中没有可观察的订阅。

如果你不需要在这些方法中返回可观察量，请尝试使用 of（），如下所示：

// DO NOT forget to import 'of' from rxjs :)
  ngOnInit(): void {
this.timeInterval = interval(5000)
.pipe(
  startWith(0),
  switchMap(() => of(this.deviceService.getDeviceList()))
)
.pipe(
  takeUntil(this.deviceService.flag$),
  repeatWhen(() => of(this.deviceService.flag$))
)
.subscribe((success: any) => {
  this.gridApi?.setRowData(this.updatedData);
  console.log("hello")
  this.updatedData = success;
}, retry(2));

Answer 2

>

首先禁用所有的测试

逐个启用，直到发现有问题的单元测试 它应该是使用模拟方法并返回可观察而不是值的提供程序，例如

｛provide:TranslateService，useValue:｛get:（）=

• 瞬间应返回值，不可观察
• getInfos应该返回一些可观察的结果，而不是未定义的
• getList应该返回可观察的数组，而不是具体的空数组

对我来说，这些案例中的任何一个都确实导致了不一致的真阴性和假阳性……

祝你好运，这个是个卑鄙的人…

Answer 3

尝试调试它:

  ngOnInit(): void {
  console.log('this.deviceService.getDeviceList()', this.deviceService.getDeviceList());
  console.log('this.deviceService.flag$', this.device.getDeviceList());

  // make sure the above logs are not defined. 
 // If they are, you're not mocking them correctly when `ngOnInit` is called. 
 // `ngOnInit` is called after the first `fixture.detectChanges()` after 
 // the `TestBed.configureTestingModule({}).compileComponents();`.

this.timeInterval = interval(5000)
.pipe(
  startWith(0),
  switchMap(() => this.deviceService.getDeviceList())
)
.pipe(
  takeUntil(this.deviceService.flag$),
  repeatWhen(() => this.deviceService.flag$)
)
.subscribe((success: any) => {
  this.gridApi?.setRowData(this.updatedData);
  console.log("hello")
  this.updatedData = success;
}, retry(2));