CODEWITHSUNDEEP
angulartypescriptcompiler-errorsobservable
Majesty
Majesty

Reputation: 2069

Angular2: Supplied parameters do not match any signature of call target

I'm created my own Observable service

import { Injectable, EventEmitter, Output} from '@angular/core';

@Injectable()
export class ObservableService {
    data = [];
    @Output eventEmitter:EventEmitter = new EventEmitter();

    setSharedData(key, value) {
        this.data[key] = value;
        this.eventEmitter.emit(this.data);
    }

    getSharedData() {
        return this.data;
    }
}

And here is an usage example

ngOnInit() {
        this._observable.eventEmitter.subscribe((data) => {
            console.log(data);
        })
    }

So currently while compiling it saying 

app/services/data-observable.service.ts(6,5): error TS1240: Unable to resolve signature of property decorator when called as an expression.
  Supplied parameters do not match any signature of call target.

Which is refers to this particular string, 

@Output eventEmitter:EventEmitter = new EventEmitter();

But the service works perfect, any suggestions what is wrong?

Upvotes: 2

Views: 3233

Answers (1)

Poul Kruijt
Poul Kruijt

Reputation: 71961

You are missing the parentheses after Output(). Although Output() is not necessary within a service. This is only necessary in a component or directive, because then you can use the (eventEmitter)="onEventEmit($event)" notation within a template.

On the other hand you are missing a type annotation for the generic EventEmitter<T>:

eventEmitter: EventEmitter<any> = new EventEmitter();

or

eventEmitter: EventEmitter<boolean> = new EventEmitter<boolean>();

Above that, EventEmitters should only be used inside @Component. If you want similar functionality, use Subject from rxjs.

subject: Subject<boolean> = new Subject<boolean>();

Upvotes: 5

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