Optimize map { ... }.compact calls (#15513)

* Optimize map { ... }.compact

using Enumerable#filter_map, supported since Ruby 2.7

* Add poyfill for Enumerable#filter_map

1 files changed, 26 insertions, 0 deletions

diff --git a/lib/enumerable.rb b/lib/enumerable.rb
new file mode 100644
index 000000000..66918f65e
--- /dev/null
+++ b/lib/enumerable.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module Enumerable
+  # TODO: Remove this once stop to support Ruby 2.6
+  if RUBY_VERSION < '2.7.0'
+    def filter_map
+      if block_given?
+        result = []
+        each do |element|
+          res = yield element
+          result << res if res
+        end
+        result
+      else
+        Enumerator.new do |yielder|
+          result = []
+          each do |element|
+            res = yielder.yield element
+            result << res if res
+          end
+          result
+        end
+      end
+    end
+  end
+end