Memoize the rendered icon tags and partials

app/helpers/icons_helper.rb

@@ -24,9 +24,11 @@ module IconsHelper
   end
 
   def custom_icon(icon_name, size: DEFAULT_ICON_SIZE)
-    # 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
+    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
@@ -46,21 +48,23 @@ module IconsHelper
   end
 
   def sprite_icon(icon_name, size: DEFAULT_ICON_SIZE, css_class: nil)
-    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)
-    end
+    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)
+      end
 
-    css_classes = []
-    css_classes << "s#{size}" if size
-    css_classes << "#{css_class}" unless css_class.blank?
+      css_classes = []
+      css_classes << "s#{size}" if size
+      css_classes << "#{css_class}" unless css_class.blank?
 
-    content_tag(
-      :svg,
-      content_tag(:use, '', { 'xlink:href' => "#{sprite_icon_path}##{icon_name}" } ),
-      class: css_classes.empty? ? nil : css_classes.join(' '),
-      data: { testid: "#{icon_name}-icon" }
-    )
+      content_tag(
+        :svg,
+        content_tag(:use, '', { 'xlink:href' => "#{sprite_icon_path}##{icon_name}" } ),
+        class: css_classes.empty? ? nil : css_classes.join(' '),
+        data: { testid: "#{icon_name}-icon" }
+      )
+    end
   end
 
   def loading_icon(container: false, color: 'orange', size: 'sm', css_class: nil)
@@ -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