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javascriptangularoopeventemitterbehaviorsubject
Jack
Jack

Reputation: 1

Should I use EventEmitter or shared Service in a reusable component in Angular?

In Angular, I have a reusable autocomplete list and I need to pass the selected option to another component where this custom component is called. However, the custom component is not called directly and there is another component between them as shown below:

Component A:          -->      Component B:       -->      Component C:      
custom-autocomplete            modal-component             employee-component

Now there are 2 option I think:

1. I can pass the selected value from Component A to any component via a shared service. But I am not sure if it is a good idea to inject a service dependency to a reusable component.

2. I can pass the selected value to Component B via EventEmitter, but I do not know if it is possible or good idea to pass the emitted event from Component B to Component C. I think I can pass the received event and parameter as I pass via EventEmitter usually, but not sure if it is a good idea.

So, what should be done in this scenario?

Upvotes: 1

Views: 536

Answers (1)

Fahad Subzwari
Fahad Subzwari

Reputation: 2325

In my opinion you should use a shared service in which you should have BehaviourSubject type observable. So whenever user will select any value form autocomplerte so you can pass that selected option to your BehaviourSubject observable and then in your another component you can subscribe to that BehaviourSubject.

And if you want to use multiple reusable autocomplete in one component so while passing each autcomplete's selected value you can pass a property named type in which you will be sending your autocomplete type.

Like you have your function like this

passDataToAnotherComponent(selectedOption: any, type: string){
   this.dataService.passData({option : selectedOption, type: type})
}

So when you call your above function for city so you will be calling in your template like this

<select (change)="passDataToAnotherComponent($event, 'city')">
   <option>City 1</option>
   <option>City 2</option>
</select>

<select (change)="passDataToAnotherComponent($event, 'department')">
   <option>department 1</option>
   <option>department 2</option>
</select>

And then in your receiving component just do like this

ngOnInit(){
   this.dataService.behaviourSubjectObservableVariable.subscribe(data => {
       if(type === 'city){
            // do somehting
       }
       if(type === 'department){
            // do somehting
       }
   })
}

Just gave a rough example to make you understand.

Upvotes: 1

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