It’s time for a new way to compose views in Ruby, using... ✨Ruby.✨ We don’t need another templating language. With Phlex, you can write small, reusable view components using simple Ruby Objects and templates composed of Ruby blocks.

Warning

Phlex is still in early development and should not be used in production yet.

The Road to 1.0

Phlex is licenced under MIT and is being developed in the open by Joel Drapper. The plan is to release a stable 1.0 version in the next few months.

If you want to help out, you can contribute by opening an issue or PR. You can also book a pairing session with me. If you work for a company that would benefit from Phlex, I accept sponsorships through GitHub.

Usage

Basic Component

You can define a component by subclassing Phlex::Component and defining a template method where you can build HTML with simple block syntax. Each HTML tag is a method that accepts keyword arguments for its attributes. Text content can be passed as the first positional argument or alternatively, you can open a block to create nested HTML tags.

class NavComponent < Phlex::Component
  def template
    nav id: "main_nav" do
      ul do
        li { a "Home", href: "/" }
        li { a "About", href: "/about" }
        li { a "Contact", href: "/contact" }
      end
    end
  end
end

Emmet-style CSS classes

It’s also possible to add classes to a tag by chaining methods calls like CSS selectors.

class CardComponent
  def template(&)
    div.shadow.rounded.p_5(&)
  end
end

Component Attributes

Components can accept arguments by defining an initializer.

class MessageComponent < Phlex::Component
  def initialize(name:)
    @name = name
  end

  def template
    h1 "Hello #{@name}"
  end
end

The default initialiser inherited from Phlex::Component sets each keyword argument to an instance variable, so the above could be re-written to call super instead.

class MessageComponent < Phlex::Component
  def initialize(name:)
    super
  end

  def template
    h1 "Hello #{@name}"
  end
end

Content

Components, like tags, can accept nested contents as a block given to template, which they can then yield or pass to another tag.

Here the content is passed to a div tag:

class CardComponent < Phlex::Component
  def template(&)
    div.rounded.drop_shadow.p_5(&)
  end
end

Here the content is yielded inside a div tag right after an h1 tag.

class CardComponent < Phlex::Component
  def initialize(title:)
    super
  end

  def template(&)
    div.rounded.drop_shadow.p_5 do
      h1 @title
      content(&)
    end
  end
end

Nested components

Components can be nested inside other components too.

class NavComponent < Phlex::Component
  def initialize(links:)
    super
  end

  def template
    nav do
      ul do
        @links.each do |label, link|
          component Nav::ItemComponent, label:, link:
        end
      end
    end
  end
end

class Nav::ItemComponent < Phlex::Component
  def initialize(label:, link:)
    super
  end

  def template
    li { a label, href: link }
  end
end

Instance variables and methods from the components are accessible deep inside nested components and tag blocks because blocks capture their context for execution.

class ArticlesComponent < Phlex::Component
  def initialize(articles:)
    super
  end

  def template
    component CardComponent, title: "Articles" do
      @articles.each do |article|
        h2 @article.title
        text @article.content
      end
    end
  end
end

Advanced components with DSLs

Becuase components accept blocks, it’s really easy to define advanced components with their own DSLs. Take, for instance, this table fabricator component that lets you define rows / columns with headers using blocks.

component Table::Fabricator, @articles, layout: :column do |t|
  t.data "Title" { a _1.title, href: article_path(_1) }
  t.text_data("Author", &:author)
  t.text_data("Published", &:published_at)
end

Other examples

This badge component takes a color argument and uses Ecase to build a list of Tailwind classes.

class BadgeComponent < Phlex::Component
  VALID_COLORS = [:sky, :teal, :rose, :slate, :orange]

  def initialize(color:)
    super
  end

  def template(&)
    span(class:, &)
  end

  private

  def class
    [:px_1, :py_1, :rounded_full, :text_sm] + colors
  end

  def colors
    ecase @color, VALID_COLORS do
      on(:sky) { [:bg_sky_200, :ring_sky_300, :text_sky_900] }
      on(:teal) { [:bg_teal_100, :ring_teal_200, :text_teal_800] }
      on(:rose) { [:bg_rose_100, :ring_rose_200, :text_rose_900] }
      on(:slate) { [:bg_slate_200, :ring_slate_300, :text_slate_800] }
      on(:orange) { [:bg_orange_200, :ring_orange_300, :text_orange_900] }
    end
  end
end

Installation

Add this line to your application's Gemfile:

gem 'phlex'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install phlex

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Phlex project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

Credits

Logo design sponsored by Logology.

casperisfine/phlex