Angular 2 and EventEmitter

Question

Hello I've started studying Angular 2. Maybe someone could help me with my question about EventEmitter and outputs in Angular 2

I have 3 components.

AppComponent is parent of CountriesListComponent .

CountriesListComponent is parent of CountryInfoComponent

AppComponent -> CountriesListComponent -> CountryInfoComponent

AppComponent has own function to listen when someone clicks on some country.

Template of AppComponent is like this:

@Component({


template: `...

< countries-list (OnCountrySelected)="countryWasClicked($event)" >
< /countries-list >
`
...

})

class AppComponent {
countryWasClicked(country: Country): void
  {

  }
}

The function OnCountrySelected is the name of output I want to listen. But I can listen it only in next child in CountriesListComponent , can't I? I want to listen OnCountrySelected in the CountryInfoComponent .

But I don't know if I can send output throught some childs.

Thanks in advance!

Answer 1

You can chain events for sure, but it is not a best practice. Like this inside the template of CountriesListComponent:

@Component({
template: `...
  < country-info (OnCountrySelected)="countryWasClicked($event)" >
  < /country-info >
`
...
})
class CountriesListComponent {
 @Output() OnCountrySelected:EventEmitter = ...
 countryWasClicked(country: Country): void
   {
     this.OnCountrySelected.emit(country);
   }
 }

But I would recommend to use (and learn) Redux approach for complex app state logic, you can use this: https://github.com/ngrx/store

Answer 2

This might help you find your answer (more specifically shared models or service events):

https://stackoverflow.com/a/34703015/6157104

Answer 3

you need an @Input() decorator in CountryInfoComponent, probably should name it country. and then in CountryListComponent you will give the selected country to the info component like this <app-country-info [country]="selectedCountry"> . selected country should be a public property of CountryListComponent. and its value can be set in your function already used to emit.

Long story short, it's an input decorator situation, not an output decorator.