Question - When we use the switchMap, mergeMap and concatMap?
Answer -
concatMap(), mergeMap(), switchMap() and exhaustMap(). All of these operators are flattening operators used to flatten observables, but they are applicable in very different scenarios. switchMap and mergeMap are probably going the be the most powerful and frequently used operators. Its is thereby critical to understand the difference between the two in order to spend less time debugging code.