javascript - 如何根据 Rails 中的属性值更改记录的颜色？

Question

我有一个带有属性卡路里和日期的入门模型。我还有带有属性 expected_calories 的 User 模型。当我显示条目列表时，如果每天的卡路里总和超过expected_calories，它应该是红色的，否则应该是绿色的。

entries_controller.rb

def index
@entries = Entry.where(user_id: current_user.id)
@user = current_user
if @user.role == 'admin'
  @entries = Entry.all
end

结束

index.html.slim

        h1 Listing entries

    table.table
      thead
        tr
          th Date
          th Time
          th Content
          th Cal
          th User
          th
          th
          th

      tbody
        - if can? :manage, Entry
          - @entries.each do |entry|
            tr
              td = entry.date
              td = entry.time.strftime("%H:%M")
              td = entry.content
              td = entry.cal
              td = entry.user.role
              td = link_to 'Show', entry
              td = link_to 'Edit', edit_entry_path(entry)
              td = link_to 'Destroy', entry, data: { confirm: 'Are you sure?' }, method: :delete

    br

    = link_to 'New Entry', new_entry_path

Answer 1

这是一种非常快速的肮脏方法:

- if can? :manage, Entry
  - @entries.each do |entry|
    tr(style="background-color: #{entry.calories > current_user.expect_calories ? 'red' : 'green'})

我建议您创建一些 css 类。例如:

.expected-calories {
  background: green
}
.unexpected-calories {
  background: green
}

然后在helpers/entries_helper中创建一个方法:

def expected_calories_class(user, entry)
  if user.expected_calories <= entry.calories
    'expected-calories'
  else
    'unexpected-calories'
  end
end

因此您的 View 将更具可读性(并且逻辑将是可测试的):

- if can? :manage, Entry
  - @entries.each do |entry|
    tr(class=expected_calories_class(current_user, entry))