How to inject a service in an exported function?

Question

I wrote a 'popping' message (android toast like) component. All other components have it as a sibling and access it via a shared service. Now I would like to use it from an utility function too, like this one:

export function handleError(errorResp: Response | any): Observable<string> {
    ....
    // here I would like to display the message
    return Observable.throw(errMsg);
}

I thought I could pass the message service as parameter to handleError, but I feel it's not DRY, as I would need to make it from every component event though the component doesn't need it for other purposes. Could you give me some guidance?

Answer 1

Since this function is outside your Angular app, there are no much options.

• Pass it via argument, or
• Directly import the service (via Javascript import, as the Angular's service is just a normal Javascript class), then use it. Note that it may not work depending on what requirements are necessary to instantiate the service (like if it uses some feature from Angular, or inject other services using DI), or
• You could place your handleError function in another service that could get the Toast thing via Dependency Injection.