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) {}