What's difference between “reduce” and “scan”

Question

I\'m studying RXJS and stuck with the problem: the same code with operators \"reduce\" and \"scan\" works in different ways, but I think that must return equal result. Example b

Answer 1

there almost the same but scan emits each iteration. and reduce just emits a final results. i like scan when i want to actually see what reduce is doing. so sometimesi . use reduce and i cant visualize what reduce is actually doing. in this case i simple swap out reduce for scan since it will emit on each iteration. this way i can put in a log statement and see the results for each iteration.