Surface

Surface is a server-side rendering component library that allows developers to build rich interactive user-interfaces, writing minimal custom Javascript.

Built on top of Phoenix LiveView and its new LiveComponent, Surface leverages the amazing Phoenix Framework to provide a fast and productive solution to build modern web applications.

Full documentation and live examples can be found at surface-ui.org.

A VS Code extension that adds support for syntax highlighting is available at marketplace.visualstudio.com.

Example

# Defining the component

defmodule Hello do
  use Surface.Component

  @doc "Someone to say hello to"
  prop name, :string, required: true

  def render(assigns) do
    ~H"""
    Hello, {{ @name }}!
    """
  end
end

# Using the component

defmodule Example do
  use Surface.Component

  def render(assigns) do
    ~H"""
    <Hello name="John Doe"/>
    """
  end
end

How does it work?

Surface’s custom compiler translates components defined in an extended HTML-like syntax into Elixir’s Abstract Syntax Tree (AST). It also translates standard HTML nodes, allowing to extend their behaviour adding new features like syntactic sugar on attributes definition, directives, static validation and more.

In order to have your code translated, you need to use the ~H sigil when defining your templates.

Features

• An HTML-centric templating language with built-in directives (:for, :if, …) and syntactic sugar for attributes (inspired by Vue.js).

• Components as modules - they can be stateless, stateful, renderless or compile-time.

• Declarative properties - explicitly declare the inputs (properties and events) of each component.

• Slots - placeholders declared by a component that you can fill up with custom content.

• Contexts - allows a parent component to share data with its children without passing them as properties..

• Compile-time checking of components and their properties.

• Integration with editor/tools for warnings/errors, syntax highlighting, jump-to-definition, auto-completion (soon!) and more.

Installation

Phoenix v1.5 comes with built-in support for LiveView apps. You can create a new application with:

mix phx.new my_app --live

Then add surface to the list of dependencies in mix.exs:

def deps do
  [
    {:surface, "~> 0.4.0"}
  ]
end

If you’re using mix format, make sure you add :surface to the import_deps configuration in your .formatter.exs file:

[
  import_deps: [:ecto, :phoenix, :surface],
  ...
]

For further information regarding installation, including how to quickly get started using a boilerplate, please visit the Getting Started guide.

Static checking

Since components are ordinary Elixir modules, some static checking is already provided by the compiler. Additionally, we added a few extra warnings to improve user experience. Here are some examples:

Module not available

Missing required property

Unknown property

Tooling

Some experimental work on tooling around the library has been done. Here’s a few of them:

VS Code

• [x] Syntax highlighting

ElixirSense

• [x] Jump to definition of modules (components)
• [ ] Jump to definition of properties
• [ ] Auto-complete/suggestions for properties (WIP)
• [x] Show documentation on hover for components
• [ ] Show documentation on hover for properties

Other tools

Having a standard way of defining components with typed properties allows us to enhance tools that introspect information from modules. One already discussed was the possibility to have ex_doc query that information to provide standard documentation for properties, events, slots, etc.

License

Copyright (c) 2020, Marlus Saraiva.

Surface source code is licensed under the MIT License.