application_helperを使う

長くてみにくかったviewの記述をapplication_helper.rbに移動させてcontent_tagと言うものを使ってhtmlタグを生成する

content_tagについて
参考: https://qiita.com/yusaku_/items/d6e98b77124131e628fb

rails/app/helpers/try_helper.rb

  def discount_text(service, provider)
    discount_price = provider.key == "noe-jx-group" ? service['discount'].to_f : service['discount'].to_i
    discount_from_energy = if SetPlan.is_discount_from_energy?(service)
      "/kWh"
    elsif SetPlan.yearly?(service)
      "/年"
    elsif SetPlan.monthly?(service)
      "/月"
    end
    content_tag(:div, class: "e__saving") do
      content_tag(:span, "割引額", class: "e__tag") + content_tag(:span, discount_price, class: "e__number e__deals" ) + "円" + discount_from_energy
    end
  end

rails/app/views/try/_set_discount.html.erb

 // 修正前
<div class="e__saving"><span class="e__tag">割引額</span><span class="e__number e__deals"><%= service['discount'].to_i %></span>円<% if SetPlan.is_discount_from_energy?(service) %>/kWh<% elsif SetPlan.monthly?(service) %>/月<% elsif SetPlan.yearly?(service) %>/年<% end %></div>

// 修正後(とっても短くなった!)
<%= discount_text(service, @provider) %>