Real-life: count() passing tests

Count how many tests returned true.

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, count } = Rx;

const tests = [true, false, true, true];

const result$ = from(tests).pipe(
  count(Boolean)
);

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