TIL: Ruby 2.7's Enumerable#filter_map

The Enumerable module is a source of wonder and crammed with so many useful methods. Today I learned about the new filter_map method.

Previously, if wanted to map only some part of a collection you would do something like:

# square only the even numbers in a range
arr = (1..10).to_a
mapped = arr.select(&:even?).map { |x| x ** 2 }

Ruby 2.7 introduced a way to combine both:

arr = (1..10).to_a
mapped = arr.filter_map { |x| x ** 2 if x.even? }

Only truthy values will be included.