Merge branch 'memoized_icon_helpers' into 'master'

Memoize the rendered icon tags and partials

See merge request gitlab-org/gitlab!47269

app/helpers/icons_helper.rb

@@ -24,10 +24,12 @@ module IconsHelper
   end
 
   def custom_icon(icon_name, size: DEFAULT_ICON_SIZE)
+    memoized_icon("#{icon_name}_#{size}") do
       # We can't simply do the below, because there are some .erb SVGs.
       #  File.read(Rails.root.join("app/views/shared/icons/_#{icon_name}.svg")).html_safe
       render "shared/icons/#{icon_name}.svg", size: size
     end
+  end
 
   def sprite_icon_path
     @sprite_icon_path ||= begin
@@ -46,6 +48,7 @@ module IconsHelper
   end
 
   def sprite_icon(icon_name, size: DEFAULT_ICON_SIZE, css_class: nil)
+    memoized_icon("#{icon_name}_#{size}_#{css_class}") do
       if known_sprites&.exclude?(icon_name)
         exception = ArgumentError.new("#{icon_name} is not a known icon in @gitlab-org/gitlab-svg")
         Gitlab::ErrorTracking.track_and_raise_for_dev_exception(exception)
@@ -62,6 +65,7 @@ module IconsHelper
         data: { testid: "#{icon_name}-icon" }
       )
     end
+  end
 
   def loading_icon(container: false, color: 'orange', size: 'sm', css_class: nil)
     css_classes = ['gl-spinner', "gl-spinner-#{color}", "gl-spinner-#{size}"]
@@ -169,4 +173,12 @@ module IconsHelper
 
     @known_sprites ||= Gitlab::Json.parse(File.read(Rails.root.join('node_modules/@gitlab/svgs/dist/icons.json')))['icons']
   end
+
+  def memoized_icon(key)
+    @rendered_icons ||= {}
+
+    @rendered_icons[key] || (
+      @rendered_icons[key] = yield
+    )
+  end
 end