ViewComponent reference

What is ViewComponent?

ViewComponent is a framework by GitHub for creating reusable, testable, and encapsulated view components in Rails. The idea is that you compose your UI from a library of components much like you would if building an app using mainly React components.

Benefits of ViewComponent

Easier to reuse and maintain

You compose your UI out of smaller components. Each component has its dependencies explicitly stated in its constructor. For example:

class MessageComponent < ViewComponent::Base
  def initialize(name:)
    @name = name
  end
end

It’s obvious what a component needs to render. In contrast, ERB views abound with mystery guests and it’s difficult to know what its dependencies are.

Testing

When your UI is complex and contains lots of Ruby logic, you can benefit from extended unit testing.

class MessageComponentTest < GitHub::TestCase
  include ViewComponent::TestHelpers

  test "renders message" do
    render_inline(MessageComponent.new(name: "World"))

    assert_selector "h1", text: "Hello, World!"
  end
end

Sources

• Official docs