What does the $ behind var$ mean?

Question

I'm learning angular7, ngrx and typescript. What does the $ behind var$ mean?

export class JokeListPage {

jokes$: Observable<Joke[]>;

constructor( public store: Store<JokeState> ){
    this.jokes$ = this.store.pipe(select(selectJokes));
    }
}

Answer 1

What does the $ behind var$ mean?

Its a naming convention for observables. If foo represents one item, foos would represent multiple foo items in English (pluralization). Using $ instead of s makes it easier to spot, hence foo$ (read foos) 🌹