The exhaustMap operator is crucial for preventing overlapping requests in Angular, ensuring that new emissions are ignored while an inner observable is still executing. With over 25 years of experience building enterprise applications and as the creator of CoreUI, I use exhaustMap to prevent duplicate form submissions and API calls. The most effective use case is for form submissions where you want to ignore subsequent submit attempts until the current request completes. This prevents race conditions and duplicate operations that could corrupt data or create inconsistent application state.

The mergeMap operator is essential for handling concurrent observables in Angular, allowing multiple HTTP requests to run in parallel without canceling previous requests. With over 25 years of experience building enterprise applications and as the creator of CoreUI, I use mergeMap for scenarios requiring parallel processing. The most effective use case is when you need to process multiple items concurrently, such as fetching details for multiple users simultaneously. This provides better performance than sequential processing while maintaining proper subscription management.