Multiple components match node with tagname app-lobby

Question

the code was running fine on angular version 8.3.4 but when i updated it to the latest version of angular ( 9 ) i got the following error

following is t

Answer 1

The two answers above about declaring DatePipe in providers should be considered. Today I met this problem (Angular 9) when adding an argument private datePipe: DatePipe in the constructor of my component without declaring DatePipe in the module's provider. After adding DatePipe in providers, I have no more the problem.

The constructor :

constructor(private authenticationService: AuthenticationService, private datePipe: DatePipe) {}

Answer 2

@VikasBhardwaj I had same problem in Angular 9 because I have created lobby page and lobby component. In this case, app-lobby is duplicated in pages and components.

@Component({
  selector: 'app-feed',

So I have changed page name as lobbies, so the problem is fixed.

Answer 3

Probably you have more than one component with the same selector tag name app-lobby

...
@Component({
   selector: 'app-lobby',
...

Please double check to ensure that only one component selector tag name is app-lobby.

Answer 4

I have an app in angular 9. I had similar problem, but then i realised that i forgot the provider for DatePipe. After that, this error went away... Maybe errors like these won't be happening after some time of angular 9 development.

Answer 5

This error actually has less to do with the tagname app-lobby. I encountered this error when I applied multiple component selector on a html tag.

For example: Component 1

@Component({
    ...
    selector: '[my-tooltip]',
    ...
})

Component 2

@Component({
    ...
    selector: '[my-button]',
    ...
})

Notice that both of them are angular component yet having a selector like attribute directive.

When you apply both of them on the same tag like below:

<button my-button my-tooltip="Some tooltip">Hover me</button>

Then angular complains about applying 2 components on a single tag. In this case it will complain about button tag, like: Error: Multiple components match node with tagname button

The solution would be not to use multiple component selector on a single element.

Answer 6

Add DatePipe in the providers.It will work fine.