Encountering a type error in Angular2 when trying to call a

Question

Encountering a type error in Angular2 when trying to call a

I am encountering an issue with a function in my service, represented by the following code:

    @Injectable()
    export class MyService {
constructor(private http: Http, private router: Router) {}
        getInfo() {
            return this.http.get(url).map((response: Response) => {return JSON.parse(response)}
        }
    }

This method is being invoked from ngOnInit of a component as shown below:

export class MyComponent implements OnInit {
    constructor(private service: MyService) { }

    ngOnInit() {
        this.service.getInfo().subscribe((data) => {
                    this.info = data;
                });
    }
}

The problem arises when navigating to this component directly through the browser URL it works fine. However, when using the router.navigate method to navigate to this component, an exception is thrown,

getInfo is not a function

Could someone please guide me on identifying the root cause of this issue and help rectify what I might be doing incorrectly?

angular typescript

Answer 1

Answer №1

If you want to make use of your service within a component, it is recommended to inject the service directly where you plan on using it. One way to achieve this is by declaring the service as a parameter in the constructor of your component. Here's an example:

simple.service.ts

@Injectable()
export class SimpleService {
    constructor(private http: Http) {}
    someMethod() { //some method }
}

some.component.ts

export class SomeComponent implements OnInit {
    constructor(private simpleService: SimpleService) { }

    ngOnInit() {
        this.simpleService.someMethod();
    }
}

It seems like there may be a missing ")" character in your service's method. It should actually look like this:

return this.http.get(url).map((response: Response) => {return JSON.parse(response)})

Alternatively, you could also simplify it to:

return this.http.get(url).map((response: Response) => response.json())

Answer 2

If you want to make use of your service within a component, it is recommended to inject the service directly where you plan on using it. One way to achieve this is by declaring the service as a parameter in the constructor of your component. Here's an example:

simple.service.ts

@Injectable()
export class SimpleService {
    constructor(private http: Http) {}
    someMethod() { //some method }
}

some.component.ts

export class SomeComponent implements OnInit {
    constructor(private simpleService: SimpleService) { }

    ngOnInit() {
        this.simpleService.someMethod();
    }
}

It seems like there may be a missing ")" character in your service's method. It should actually look like this:

return this.http.get(url).map((response: Response) => {return JSON.parse(response)})

Alternatively, you could also simplify it to:

return this.http.get(url).map((response: Response) => response.json())

Encountering a type error in Angular2 when trying to call a

Answer №1

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