A UI component library for Phlex using tailwindcss and daisyUI.
You can see a full list of the components at https://protos.inhouse.work/.
Other Phlex based UI libraries worth checking out:
Thinking of making your next static site using Phlex? Check out staticky. The protos docs were published using it.
Phlex is a fantastic framework for building frontend components in pure Ruby:
class Navbar
def view_template
header(class: "flex items-center justify-between") do
h3 { "My site" }
button { "Log out" }
end
end
end
But how can we sometimes render this Navbar with a different background color?
It would be nice to have our components take a class like any other element:
render Navbar.new(class: "bg-primary")
Unfortunately class is a special keyword in Ruby, so we need to do some
awkward handling to use it like this:
class Navbar
def initialize(**options)
# Keyword `class` is a special word in Ruby so we have to awkwardly unwrap
# like this instead of using keyword arguments
@classes = options[:class]
end
def view_template
header(class: "#{@classes} flex items-center justify-between") do
h3 { "My site" }
button { "Log out" }
end
end
end
Now we can pass in a style to our container, but what about overriding the style
of the h3 tag?
class Navbar
def initialize(**options)
# Keyword `class` is a special word in Ruby so we have to awkwardly unwrap
# like this instead of using keyword arguments
@container_classes = options[:class]
@title_classes = options[:title_class]
end
def view_template
header(class: "#{@classes} flex items-center justify-between") do
h3(class: @title_classes) { "My site" }
button { "Log out" }
end
end
end
Eventually everyone makes a kind of ad-hoc system for specifying styles.
It gets more complicated when you have attributes like a data-controller. How do you give a good experience letting people using your components to add their own controllers while your component depends on one already?
This library is an attempt to make this kind of developer experience while making reusable components more convention over configuration.
A protos component follows 3 conventions that make them easy to work with as components in your app:
Every UI component library will have a tension between being too general to fit in your app or too narrow to be useful. Making components that look good out of the box can make them hard to customize.
We try and resolve this tension by making these components have a minimal style that can be easily overridden using some ergonomic conventions.
Components are styled with css slots that get their values from a simple hash
we call a theme.
You define a theme for your component by defining a #theme method that
returns a hash.
Users of your components can override, merge, or remove parts of your theme by passing in their own as an argument to the component. Another nice benefit is that your markup doesn't get overwhelmed horizontally with your css classes.
class List < Protos::Component
def view_template
ul(class: css[:list]) do
li(class: css[:item]) { "Item 1" }
li(class: css[:item]) { "Item 2" }
end
end
def theme
{
list: ["space-y-4"], # We can use arrays
item: "font-bold text-2xl" # Or just plain old strings
}
end
end
Using a theme and css slots allows us to easily override any part of a component when we render.
Here we are passing in our own theme. The default behavior is to add these styles on to the theme, rather than replacing them.
render List.new(
theme: {
list: "space-y-8",
item: "bg-red-500"
}
)
When the component is rendered the tailwind_merge gem will also prune any
duplicate unneeded styles.
For example even though the themes list key would be added together to become
space-y-4 space-y-8, the tailwind_merge gem will prune it down to just
space-y-8 as the two styles conflict.
<ul class="space-y-8">
<li class="font-bold text-2xl bg-red-500">Item 1</li>
<li class="font-bold text-2xl bg-red-500">Item 2</li>
</ul>
We can override the slot entirely by using a ! at the end of the key:
render List.new(
theme: {
item!: "bg-red-500"
}
)
The css slot css[:item] would be overridden rather than merged:
<li class="bg-red-500">Item 1</li>
We can also negate a certain class or classes from the slot by putting a !
at the start of the key:
render List.new(
theme: {
"!item": "text-2xl"
}
)
The new css[:item] slot would be:
<li class="font-bold">Item 1</li>
Slots can also take multiple arguments, and even inline styles:
class ListItem < Protos::Component
def view_template
li(class: css[:item, :primary_item, "text-sm"])
end
end
This combines the styles together, removing any duplicates.
By convention, all components spread in an attrs hash on their outermost
element of the component. There is no rule for this, but it makes them feel more
naturally like native html elements when you render them.
By doing this we enable 3 main conveniences:
class keyword when initializing the component which will be
merged safely into the css[:container] slotid, data
etc and it will just workclass List < Protos::Component
def view_template
ul(**attrs) do
# ...
end
end
private
def default_attrs
{
data: { controller: "list" }
}
end
def theme
{
container: "space-y-4",
item: "font-bold"
}
end
end
#attrs returns a hash which will by default merge the class keyword into the
css[:container] slot which we define in our theme. The ul elements class
would be space-y-4 as that is the css[:container] on our theme.
Special html options (class, data) will be safely merged.
For examples, the component above defines a list controller. If we passed our own controller into data when we initialize, the component's data-controller attribute would be appended to:
render List.new(
data: { controller: "tooltip" }
)
That would output both controllers to the DOM element:
<ul data-controller="list tooltip">
This makes it very convenient to add functionality to basic components without overriding their core behavior or having to modify/override their class.
Components extend
Dry::Initializer
which lets us easily add new positional arguments with param or keyword
arguments with option
class List < Protos::Component
option :ordered
end
This makes our initialization declarative and easy to extend without having to
consider how to call super in the initializer.
The following keywords are reserved in the base class:
classthemehtml_optionsYou are free to add whatever positional or keyword arguments you like as long as they don't directly conflict with those names.
Lets revisit the example of our Navbar component:
require "protos"
class Navbar < Protos::Component
def view_template
header(**attrs) do
h1(class: css[:heading]) { "Hello world" }
h2(class: css[:subtitle]) { "With a subtitle" }
end
end
private
def default_attrs
{
data: { controller: "navbar" }
}
end
def theme
{
container: "flex justify-between items-center gap-sm",
heading: "text-2xl font-bold",
subtitle: "text-sm"
}
end
end
Now all the concerns about adding in our behavior, styles, etc are handled for us by convention:
render Navbar.new(
# This will add to the component's css[:container] slot
class: "my-sm",
# This will add the controller and not remove
# the existing one
data: { controller: "counter" },
theme: {
heading: "p-sm", # We can add tokens
"!container": "gap-sm" # We can negate (remove) certain tokens
subtitle!: "text-xl" # We can override the entire slot
}
)
Which produces the following html:
<header data-controller="navbar counter" class="flex justify-between items-center my-sm">
<h1 class="text-2xl font-bold p-sm">Hello world</h1>
<h2 class="text-xl">With a subtitle</h2>
</header>
Install the gem and add to the application's Gemfile by executing:
$ bundle add protos
If bundler is not being used to manage dependencies, install the gem by executing:
$ gem install protos
Setup TailwindCSS, DaisyUI and add the protos path to your content.
npm install -D tailwindcss postcss autoprefixer daisyui
npx tailwindcss init
Then we need to add the protos path to the content of our tailwind config
so tailwind will read the styles defined in the Protos gem.
Protos also uses semantic spacing such as p-sm or m-md instead of set
numbers so you can easily choose the spacing you want. So we will need to extend
spacing in your theme.
// tailwind.config.js
// For importing tailwind styles from protos gem
const execSync = require('child_process').execSync;
const outputProtos = execSync('bundle show protos', { encoding: 'utf-8' });
const protos_path = outputProtos.trim() + '/**/*.rb';
module.exports = {
content: [
"./app/views/**/*.{rb,html,html.erb,erb}",
protos_path
],
theme: {
extend: {
spacing: {
xs: "var(--spacing-xs)",
sm: "var(--spacing-sm)",
md: "var(--spacing-md)",
lg: "var(--spacing-lg)",
xl: "var(--spacing-xl)",
},
},
}
// ....
}
Add protos-stimulus
to your packages:
npm install protos-stimulus
And somewhere in your entrypoints import as a side effect:
import "protos-stimulus"
Then you can use the components in your apps.
Protos::Card.new(class: "bg-base-100") do |card|
card.body(class: "gap-sm") do
card.title(class: "font-bold") { "Hello world" }
span { "This is some more content" }
card.actions do
button(class: "btn btn-primary") { "Action 1" }
end
end
end
You can override components simply by redefining sub-classing the class in your own app:
module Components
class Swap < Protos::Component
private
def on(...)
MyOnButton.new(...)
end
def theme
super.merge({
input: ["block", "bg-red-500"]
})
end
end
end
But its much better to avoid the sub-classing and just render the component inside of your own:
module Components
class Swap < ApplicationComponent
def view_template
render Protos::Swap.new do |c|
# ....
end
end
end
end
You could use Proto::List to create your own list and even use some kind of
DeferredRender
to make the API more convenient.
Let's create a list component with headers and actions:
module DeferredRender
def before_template(&)
vanish(&)
super
end
end
module Ui
class List < Protos::Component
include Protos::Typography
include DeferredRender
option :title, default: -> {}
option :ordered, default: -> { false }
option :items, default: -> { [] }, reader: false
option :actions, default: -> { [] }, reader: false
def template
article(**attrs) do
header class: css[:header] do
h3(size: :md) { title }
nav(class: css[:actions]) do
@actions.each do |action|
render action
end
end
end
render Protos::List.new(ordered:, class: css[:list]) do
@items.each { |item| render item }
li(&@empty) if @items.empty?
end
end
end
def with_item(*, **, &block)
theme = { container: css[:item] }
@items << Protos::List::Item.new(*, theme:, **, &block)
end
def with_action(&block)
@actions << block
end
def with_empty(&block)
@empty = block
end
private
def theme
{
container: "space-y-xs",
header: "flex justify-between items-end gap-sm",
list: "divide-y border w-full",
actions: "space-x-xs",
item: "p-sm"
}
end
end
end
Now the component is specific to our application, and the styles are still overridable at all levels:
render Ui::List.new(title: "Project Names", ordered: true) do |list|
list.with_action { link_to("Add item", "#") }
list.with_item(class: "active") { "Project 1" }
list.with_item { "Project 2" }
list.with_item { "Project 3" }
end
Or here is another example of a table:
module Ui
class Table < ApplicationComponent
include Protos::Typography
include DeferredRender
class Column
attr_reader :title
def initialize(title, &block)
@title = title
@block = block
end
def call(item)
@block.call(item)
end
end
option :title, default: -> {}
option :collection, default: -> { [] }, reader: false
option :columns, default: -> { [] }, reader: false
option :actions, default: -> { [] }, reader: false
def template
article(**attrs) do
header class: css[:header] do
h3(size: :md) { title } if title.present?
nav(class: css[:actions]) do
@actions.each do |action|
render action
end
end
end
render Protos::Table.new(class: css[:table]) do |table|
render(table.caption(class: css[:caption]), &@caption) if @caption
render table.header do
render table.row do
@columns.each do |column|
render table.head do
plain(column.title)
end
end
end
end
render table.body do
@collection.each do |item|
render table.row do
@columns.each do |column|
render table.cell do
column.call(item)
end
end
end
end
if @collection.empty?
render table.row do
render table.cell(colspan: @columns.length) do
@empty&.call
end
end
end
end
end
end
end
def with_column(...)
@columns << Column.new(...)
end
def with_empty(&block)
@empty = block
end
def with_caption(&block)
@caption = block
end
def with_action(&block)
@actions << block
end
private
def theme
{
container: "space-y-sm",
header: "flex justify-between items-end gap-sm",
table: "border",
caption: "text-muted"
}
end
end
end
Which lets you have a very nice table builder:
collection = [
{
name: "John Doe",
status: "Active",
location: "New York"
}
]
render Ui::Table.new(title: "A table", collection:) do |table|
table.with_caption { "Users" }
table.with_action do
a(href: "#") { "Add new" }
end
table.with_column("Name") { |row| row[:name] }
table.with_column("Location") { |row| row[:location] }
table.with_column("Status") do |row|
span(class: "badge badge-info") { row[:status] }
end
table.with_column("Actions") do
a(href: "#") { "View" }
end
end
Here is a list that we don't yet have components for:
After checking out the repo, run bin/setup to install dependencies. Then, run
rake spec to run the tests. You can also run bin/console for an interactive
prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To
release a new version, update the version number in version.rb, and then run
bundle exec rake release, which will create a git tag for the version, push
git commits and the created tag, and push the .gem file to
rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/inhouse-work/protos.
You can run the benchmarks using the raketasks, e.g:
bin/rake benchmark:ips:tablebin/rake benchmark:memory:tablebin/rake benchmark:ips:themebin/rake benchmark:ips:attributesThere are also tasks for profiling and exploring memory consumption.
You can find the latest benchmarks in benchmarks/. These were run on a new
Macbook M3 Pro chip.
Currently this library is 30x slower than plain Phlex components. This is due to the overhead of themes, attributes and other quality of life improvements.
This may seem like a lot but Phlex is so fast that rendering a large table can still be done 4000 times per second with this lib.
The gem is available as open source under the terms of the MIT License.
FAQs
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We found that protos demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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