ViewComponent

ViewComponent is a framework for creating reusable, testable & encapsulated view components with Ruby on Rails, without the need for a JavaScript framework like Vue. They are rendered server-side and can be seamlessly used with template languages like Haml.

For more information, see the official documentation or this introduction video.

Browse components with Lookbook

We have a Lookbook in http://gdk.test:3000/rails/lookbook (only available in development mode) to browse and interact with ViewComponent previews.

Pajamas components

Some of the components of our Pajamas design system are available as a ViewComponent in app/components/pajamas.

Available components

Consider this list a best effort. The full list can be found in app/components/pajamas. Also see our Lookbook (http://gdk.test:3000/rails/lookbook) for a more interactive way to browse our components.

Alert

The Pajamas::AlertComponent follows the Pajamas Alert specification.

Examples:

By default this creates a dismissible info alert with icon:

= render Pajamas::AlertComponent.new(title: "Almost done!")

You can set variant, hide the icons and more:

= render Pajamas::AlertComponent.new(title: "All done!",
  variant: :success,
  dismissible: :false,
  show_icon: false)

For the full list of options, see its source.

Banner

The Pajamas::BannerComponent follows the Pajamas Banner specification.

Examples:

In its simplest form the banner component looks like this:

= render Pajamas::BannerComponent.new(button_text: 'Learn more', button_link: example_path,
  svg_path: 'illustrations/example.svg') do |c|
  - c.with_title { 'Hello world!' }
  %p Content of your banner goes here...

If you have a need for more control, you can also use the illustration slot instead of svg_path and the primary_action slot instead of button_text and button_link:

= render Pajamas::BannerComponent.new do |c|
  - c.with_illustration do
    = custom_icon('my_inline_svg')
  - c.with_title do
    Hello world!
  - c.with_primary_action do
    = render 'my_button_in_a_partial'

For the full list of options, see its source.

Button

The Pajamas::ButtonComponent follows the Pajamas Button specification.

Examples:

The button component has a lot of options but all of them have good defaults, so the simplest button looks like this:

= render Pajamas::ButtonComponent.new do |c|
  = _('Button text goes here')

The following example shows most of the available options:

= render Pajamas::ButtonComponent.new(category: :secondary,
  variant: :danger,
  size: :small,
  type: :submit,
  disabled: true,
  loading: false,
  block: true) do |c|
  Button text goes here

You can also create button-like looking <a> tags, like this:

= render Pajamas::ButtonComponent.new(href: root_path) do |c|
  Go home

For the full list of options, see its source.

Card

The Pajamas::CardComponent follows the Pajamas Card specification.

Examples:

The card has one mandatory body slot and optional header and footer slots:

= render Pajamas::CardComponent.new do |c|
  - c.with_header do
    I'm the header.
  - c.with_body do
    %p Multiple line
    %p body content.
  - c.with_footer do
    Footer goes here.

If you want to add custom attributes to any of these or the card itself, use the following options:

= render Pajamas::CardComponent.new(card_options: {id: "my-id"}, body_options: {data: { count: 1 }})

header_options and footer_options are available, too.

For the full list of options, see its source.

Checkbox tag

The Pajamas::CheckboxTagComponent follows the Pajamas Checkbox specification.

The name argument and label slot are required.

For example:

= render Pajamas::CheckboxTagComponent.new(name: 'project[initialize_with_sast]',
  checkbox_options: { data: { testid: 'initialize-with-sast-checkbox', track_label: track_label, track_action: 'activate_form_input', track_property: 'init_with_sast' } }) do |c|
  - c.with_label do
    = s_('ProjectsNew|Enable Static Application Security Testing (SAST)')
  - c.with_help_text do
    = s_('ProjectsNew|Analyze your source code for known security vulnerabilities.')
    = link_to _('Learn more.'), help_page_path('user/application_security/sast/_index.md'), target: '_blank', rel: 'noopener noreferrer', data: { track_action: 'followed' }

For the full list of options, see its source.

Checkbox

The Pajamas::CheckboxComponent follows the Pajamas Checkbox specification.

For the full list of options, see its source.

Toggle

The Pajamas::ToggleComponent follows the Pajamas Toggle specification.

= render Pajamas::ToggleComponent.new(classes: 'js-force-push-toggle',
  label: s_("ProtectedBranch|Toggle allowed to force push"),
  is_checked: protected_branch.allow_force_push,
  label_position: :hidden) do
  Leverage this block to render a rich help text. To render a plain text help text, prefer the `help` parameter.

For the full list of options, see its source.

Layouts

Layout components can be used to create common layout patterns used in GitLab.

Available components

Page heading

A standard page header with a page title and optional actions.

Example:

= render ::Layouts::PageHeadingComponent.new(_('Page title')) do |c|
  - c.with_actions do
    = buttons

For the full list of options, see its source.

CRUD component

A list container being used to host a table or list with user actions such as create, read, update, delete.

Example:

= render ::Layouts::CrudComponent.new(_('CRUD title'), icon: 'ICONNAME', count: COUNT) do |c|
  - c.with_description do
    = description
  - c.with_actions do
    = buttons
  - c.with_form do
    = add item form
  - c.with_body do
    = body
  - c.with_pagination do
    = pagination component
  - c.with_footer do
    = optional footer

For the full list of options, see its source.

Horizontal section

Many of the settings pages use a layout where the title and description are on the left and the settings fields are on the right. The Layouts::HorizontalSectionComponent can be used to create this layout.

Example:

= render ::Layouts::HorizontalSectionComponent.new(options: { class: 'gl-mb-6' }) do |c|
  - c.with_title { _('Naming, visibility') }
  - c.with_description do
    = _('Update your group name, description, avatar, and visibility.')
    = link_to _('Learn more about groups.'), help_page_path('user/group/_index.md')
  - c.with_body do
    .form-group.gl-form-group
      = f.label :name, _('New group name')
      = f.text_field :name

For the full list of options, see its source.

Settings block

A settings block (accordion) to group related settings.

Example:

= render ::Layouts::SettingsBlock.new(_('Settings block heading')) do |c|
  - c.with_description do
    = description
  - c.with_body do
    = body

For the full list of options, see its source.

Settings section

Similar to SettingsBlock (see above) this component is used to group related settings together. Unlike SettingsBlock it doesn’t provide accordion functionality. Uses a sticky header.

Example:

= render ::Layouts::SettingsSection.new(_('Settings section heading')) do |c|
  - c.with_description do
    = description
  - c.with_body do
    = body

For the full list of options, see its source.

Best practices

• If you are about to create a new view in Haml, use the available components over creating plain Haml tags with CSS classes.
• If you are making changes to an existing Haml view and see, for example, a button that is still implemented with plain Haml, consider migrating it to use a ViewComponent.
• If you decide to create a new component, consider creating previews for it, too. This will help others to discover your component with Lookbook, also it makes it much easier to test its different states.

Preview layouts

If you need to have a custom layout for your ViewComponent preview consider using these paths for the layout code:

• app/views/layouts/lookbook for your layout HAML file
• app/assets/javascripts/entrypoints/lookbook for your custom JavaScript code
• app/assets/stylesheets/lookbook for your custom SASS code

JavaScript and SASS code have to be manually included in the layout.