How to Return Observable from inside Observable

Question

I have this code that grabs a cached value:

getConfigurations(): Observable<SiteConfiguration[]> {
    return this.storageService.getSiteConfigurations().map(c => {
        if(c) {
            return c;
        }                         
        return this.httpClient.get<SiteConfiguration[]>(this.url + "/config").subscribe(c => c);
    });        
}

I cache the SiteConfiguration object, but need to go to the server to get it if it doesn't exist. But I can't return the second observable inside the first, as it would be returning an Observable<Observable<SiteConfiguration[]>>.

I'm sure this is a common scenario but my google-fu failed to find an answer.

Answer 1

your code should look like this

getConfigurations(): Observable<SiteConfiguration[]> {
    return this.storageService.getSiteConfigurations().flatMap(c => {
        if(c) {
            return Obserbable.of(c);
        }                         
        return this.httpClient.get<SiteConfiguration[]>(this.url + "/config")
    })        
}



getCOnfiguration().subscribe(c => c);