Reconciling React as a View Layer Replacement

Zach Lendon @zachlendon

#reactjs #midwestjs #reactjsisawesome

https://github.com/zachlendon/midwestjs2014

Traditional JS MV* “issues”

•“State” •Performance •Complexity •Predictability •Testability

• Isomorphic Javascript • The right simple :: powerful ratio • The right configurable :: opinionated ratio • Pluggable modular architecture • Performant • SEO

Top keys to future “web” MV* framework success

“State” of the JS MV*

Meet React

•A Javascript Library for Creating User Interfaces •https://github.com/facebook/react •Open Sourced and Battle-tested by Facebook and

Instagram •Browser support to IE8

“React is not a full MVC framework, and this is actually one of its strengths. Many who adopt React choose to do so alongside their favorite MVC framework, like Backbone. React has no opinions about routing or syncing data, so you can easily use your favorite tools to handle those aspects of your frontend application. You'll often see React used to manage specific parts of an application's UI and not others. React really shines, however, when you fully embrace its strategies and make it the core of your application's interface.”

@bkonkle: http://lincolnloop.com/blog/architecting-your-app-react-part-1/

Why React?

• “State” is what makes building UIs hard • “Data Changing over time is the Root of All Evil”

React Solution

Use composable React components that effectively re-render themselves on each state mutation

•Apple •Oranges

•Apple •Grapes •Bananas

React

Before After

Virtual DOM

•In-memory representation of the DOM and events system •Even HTML5 events in IE8

Advantages of Virtual DOM

•Interacting with DOM -> Slow, •with Javascript In-Memory Objects -> fast

•60 fps fast •Faster parsing •Faster Validation

•Since no real browser, can easily render on server or client

•Easier To Test

Fallout Advantages of Virtual DOM include

•Autobinding •Event Delegation

http://lincolnloop.com/blog/architecting-your-app-react-part-1/

React Components

React Components translate raw data into rich HTML

The Ultimate State Machine

React Components

React.createClass({..})

The Ultimate State Machine

Render: “pure” Javascript function

http://jsfiddle.net/zlendon/9xyn3/

Render: “pure” Coffeescript function

http://jsfiddle.net/zlendon/32xj5/

Render: Better “pure” Coffeescript function

http://jsfiddle.net/zlendon/32xj5/1/

Render: “JSX” Javascript function

http://jsfiddle.net/zH5YG/

JSX “Desugared” to native Javascript

Rules of Render•Return a single child component

•Native DOM component •Composite Component

•Return predictable result each time invoked •Does not touch the DOM (read or write) or interact with the

browser (i.e., setTimeout) !

Rules of Server Side Render

!!!

!

•renderComponentToString on server •render on client, to same node, preserves server-rendered

markup and adds event handlers

•http://www.princeton.edu/~crmarsh/react-ssr/ (Charlie Marsh)

•https://github.com/andreypopp/react-async •https://github.com/karlmikko/bleeding-edge-

sample-app/blob/react-router/server/render/render.js (soon to be in React-Router)

tl&dr;

React Components: Input

•Props: immutable data specific to an instance of a component •Like params into a function

•State: Private mutable attribute. Change within which trigger scheduling of a component re-render

Both Props and State

• Are plain JS objects • Changes trigger a render update • Are deterministic. If your Component generates different outputs for

the same combination of props and state then you're doing something wrong.

https://github.com/uberVU/react-guide/blob/master/props-vs-state.md#readme

Rules of State•Belong to only one component •Within that component, modified 2 ways

•getInitialState •setState

•Render returns same result each time invoked with same state

•Do not use computed data or duplicate prop data as state •Avoid using state when possible •Do not change state of children components

Rules of Props

•Passed from the parent • Immutable •Often pass callback functions through them !

Component LifecycleMounting • componentWillMount() • componentDidMount() !Updating • componentWillReceiveProps(object nextProps) • boolean shouldComponentUpdate(object nextProps, object nextState) • componentWillUpdate(object nextProps, object nextState) • componentDidUpdate(object prevProps, object prevState) !Unmounting • componentWillUnmount()

Mixins

•Cross cutting concerns

•Examples: •ReactScriptLoader: https://github.com/yariv/ReactScriptLoader •ReactIntlMixin: https://github.com/yahoo/react-intl •Backbone.React.Component.mixin: https://github.com/

magalhas/backbone-react-component

Scaling React

!!!

!

Action Controller Model View

Conference MVC

• Modified from Flux into by Jing Chen at F8, 2014

Scaling with React

!!!

!

Action Controller Model ViewModelModel

Model

Model

Model

View

View

View

View

View

View

Real World MVC

Scaling with React

!!!

!

Action Dispatcher Store View

Action

Flux

Starting a New App: React•Lots of Great “Full-Stack” Starter Kit Options - Many Listed:

https://github.com/facebook/react/wiki/Complementary-Tools

New Project w/ Routing•React Boilerplate: https://github.com/rackt/react-boilerplate •Uses:

•React-router (prev. react-nested-router) •Translation of Ember Router API to React

•Webpack •pushstate-serv

New Project w/o Routing•https://github.com/newtriks/generator-react-webpack •Yeoman Generator •Uses:

•Webpack •Grunt •Karma

New Project w/ Routing & Server-side Rendering:

•React Quickstart: •https://github.com/newtriks/generator-react-webpack

•Uses: •react-router-component •react-async •express •browserify •npm

New Project: Midwest JS Demo

•React Boilerplate •Plus:

•Express (3) •Bootstrap 3

DEMO DISCUSSION

Adding React To Existing Project

“We don’t need to switch to React everywhere, all at once. It’s not a framework that imposes anything on the application structure. [...] Easy, iterative adoption is definitely something in React’s favor for us.”

!

-Adobe Brackets Team

Backbone Views

•Nested Backbone.View’s are difficult to maintain •Every collection change re-renders all views

Simple Backbone Port

Integration with Backbone Models and Collections

•Trigger React re-render on Backbone model “change” events

Mixins! Maybe

Lost shouldComponentUpdate hooks

TODO MVC: React + Backbone

Mixins! MaybeBackbone-React-Component

Mixins! MaybeBackbone-React-Component

Use State Callback

Use State Callback

Angular and React

Angular Directives Wrapping React

•ngReact

•ngReactGrid

Angular ngReactGrid Demo

Integration Lessons•You can integrate React with other frameworks •Backbone integration works better than many options since re-

rendering on model state change is the typical Backbone approach

•Angular will work best from directives but is a bit of a force fit •Best approach to let React own the DOM element being

rendered into

(Beyond the Obvious) Additional Resources (1/2)•Great Collection of Community links:

https://github.com/mindreframer/reactjs-stuff •Developing User Interfaces with React: http://youtu.be/

1OeXsL5mr4g?list=PLuE9Gq9Mxr5kCvVa7tcwW1S2-FEym5fbt (intro + good performance demo)

•Good Flux intro by Ryan Florence: http://vimeo.com/102953099

•Thorough and infamous Angular/ReactJS performance/integration post: http://www.williambrownstreet.net/blog/2014/04/faster-angularjs-rendering-angularjs-and-reactjs/

•Performance Tools: http://facebook.github.io/react/docs/perf.html

!

(Beyond the Obvious) Additional Resources (2/2)

!•Webpack Howto: https://github.com/petehunt/webpack-

howto •Webpack Hot Module Replacement: https://github.com/

webpack/docs/wiki/hot-module-replacement-with-webpack •Om: https://github.com/swannodette/om •Jest: http://facebook.github.io/jest/

Thank You

Questions?

Zach Lendon @zachlendon

#reactjs #midwestjs https://github.com/zachlendon

#reactjs on freenode