Interview: windowCount() streaming batches

Split a stream of numbers into Observable windows of 2 values and collect each window into a string.

1. Solve the task in the editor — no long theory.
2. Run the check and compare your output with the expected result.
3. Stuck? Open the solution and carry the approach into your own code.

const { from, windowCount, mergeMap, toArray, map } = Rx;

const result$ = from([1, 2, 3, 4, 5]).pipe(
  windowCount(2),
  mergeMap(window$ => window$.pipe(toArray(), map(values => values.join('-'))))
);

result$.subscribe(value => console.log(value));