Clearwater is a rich front-end framework for building fast, reasonable, and easily composable browser applications in Ruby. It renders to a virtual DOM and applies the virtual DOM to the browser's actual DOM to update only what has changed on the page.
Add these lines to your application's Gemfile:
gem 'clearwater', '~> 1.0.0.rc2'
gem 'opal-rails' # Only needed for Rails apps
Clearwater has three distinct parts:
- The component: the presenter and template engine
- The router: the dispatcher and control
- The application: the "Go" button
The Component
class Blog
# All components need a set of behavior, but don't worry it's not a massive list.
include Clearwater::Component
# This method needs to return a virtual-DOM element using the element DSL.
# The DSL is provided by the Clearwater::Component mixin.
def render
div([
Articles.new,
Biography.new,
])
end
end
While we use two components in this example, you can use all of these as well:
# <div id="foo">
# <h1>Heading</h1>
# <article>hello!</article>
# </div>
def render
div({ id: 'foo' }, [
h1('Heading'),
article('hello!'),
])
end
# <div>Hello, world!</div>
def render
div('Hello, world!')
end
# <div>123</div>
def render
div(123)
end
# <div></div>
def render
div
end
The Router
router = Clearwater::Router.new do
# A route with a block contains subordinate routes
route 'blog' => Blog.new do # /blog
route 'new_article' => NewArticle.new # /blog/new_article
# This path contains a dynamic segment. Inside this component, you can use
# router.params[:article_id] to return the value for this segment of the
# URL. So for "/articles/123", router.params[:article_id] would be "123".
route ':article_id' => ArticleReader.new # /blog/123
end
end
You can also use Clearwater as part of the Rails asset pipeline. First create your Clearwater application (replace app/assets/application.js
with this file):
# file: app/assets/javascripts/application.rb
require 'opal' # Not necessary if you load Opal from a CDN
require 'clearwater'
class Layout
include Clearwater::Component
def render
h1('Hello, world!')
end
end
app = Clearwater::Application.new(component: Layout.new)
app.call
Then, in app/views/layouts/application.html.erb
:
<!DOCTYPE html>
<html>
<!-- snip -->
<body>
<!--
We load the JS in the body tag to ensure the element exists so we can
render to it. Otherwise, we need to use events on the document before we
instantiate and call the Clearwater app. And that's no fun.
-->
<%= javascript_include_tag 'application' %>
</body>
</html>
Then just create a root route that renders a blank template and refresh the page. You should see "Hello, world!" in big, bold letters. Congrats! You've built your first Clearwater app on Rails!
require 'opal'
require 'clearwater'
require 'ostruct'
class Layout
include Clearwater::Component
def render
div({ id: 'app' }, [
header({ class_name: 'main-header' }, [
h1('Hello, world!'),
]),
outlet, # This is what renders subordinate routes
])
end
end
class Articles
include Clearwater::Component
def render
div({ id: 'articles-container '}, [
input({ class_name: 'search-articles', onkeyup: method(:search) }),
ul({ id: 'articles-index' }, articles.map { |article|
ArticlesListItem.new(article)
}),
outlet, # This is what renders subordinate routes (e.g. Article)
])
end
def articles
@articles ||= MyStore.fetch_articles
if @query
@articles.select { |article| article.match?(@query) }
else
@articles
end
end
def search(event)
@query = event.target.value
call # Rerender the app
end
end
class ArticlesListItem
include Clearwater::Component
attr_reader :article
def initialize(article)
@article = article
end
def render
# Note the "key" key in this hash. This is a hint to the virtual DOM that
# if this node is moved around, it can still reuse the same element.
li({ key: article.id, class_name: 'article' }, [
# The Link component will rerender the app for the new URL on click
Link.new({ href: "/articles/#{article.id}" }, article.title),
time({ class_name: 'timestamp' }, article.timestamp.strftime('%m/%d/%Y')),
])
end
end
class Article
include Clearwater::Component
def render
# In addition to using HTML5 tag names as methods, you can use the `tag`
# method with a query selector to generate a tag with those attributes.
tag('article.selected-article', nil, [
h1({ class_name: 'article-title' }, article.title),
time({ class_name: 'article-timestamp' }, article.timestamp.strftime('%m-%d-%Y')),
section({ class_name: 'article-body' }, article.body),
])
end
def article
# params[:article_id] is the section of the URL that contains what would be
# the `:article_id` parameter in the router below.
MyStore.article(params[:article_id])
end
def match? query
query.split.all? { |token|
title.include?(token) || body.include?(token)
}
end
end
module MyStore
extend self
DB = 5.times.map do |n|
OpenStruct.new(id: n, timestamp: Time.new, title: "Random thoughts n.#{n}", body: 'Some deep stuff')
end
def fetch_articles
DB
end
def article(id)
id = id.to_i
DB.find {|a| a.id == id}
end
end
router = Clearwater::Router.new do
route 'articles' => Articles.new do
route ':article_id' => Article.new
end
end
MyApp = Clearwater::Application.new(
component: Layout.new,
router: router,
element: Bowser.document.body # This is the default target element
)
MyApp.call # Render the app.
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Copyright (c) 2014-2015 Jamie Gaskins
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