Comparisons

Interviewers rarely ask "what does switchMap do?" in isolation. They ask "when would you use switchMap instead of mergeMap?" These pages put similar tools side by side so you can answer with confidence, and revise quickly before an interview.

Available comparisons

• switchMap vs mergeMap vs concatMap vs exhaustMap: the higher-order mapping strategies. Cancellation vs concurrency vs strict ordering vs ignore-while-busy, and which real scenarios call for each.
• Subject vs BehaviorSubject vs ReplaySubject: what a new subscriber receives from each Subject type and how to choose.

Related quick reads

• EMPTY vs NEVER: two observables that emit nothing, with very different completion behavior.
• Promise vs Observable: the classic interview opener.
• Cold vs Hot observables: per-subscriber execution vs shared live streams.