What does puts [1, 2, 3, 4, 5].filter_map { |x| x * 2 if… output?

Console output

Why

`Enumerable#filter_map` combines `select` and `map`. The `if x.odd?` returns `nil` for even numbers (which are excluded). Odd numbers `1, 3, 5` are doubled, producing `[2, 6, 10]`.