The Evolution of Airbnb's Frontend

The Evolution of Airbnb’s Frontend ! @spikebrehm

Spike Brehm ____________________________ @spikebrehm ! @AirbnbNerds since 2011

1. A Brief History of airbnb.com 2. Modernizing our JavaScript Stack 3. Airbnb&Isomorphic JavaScript

A Brief History of airbnb.com

! airbedandbreakfast.com2008

! airbnb.com2009

Rails 2.x MySQL Vanilla CSS Prototype.js !2009

Rails 3.x, Java MySQL, Redis, HDFS, Postgres, DynamoDB SASS, O2 jQuery, Backbone, Handlebars !2012

! Bootstrap-inspired CSS frameworkO2

Rails 3.x, Java, Node.js MySQL, Redis, HDFS, Postgres, DynamoDB, Kafka, RabbitMQ, … SASS, O2 jQuery, Backbone, Handlebars, React, CommonJS, ES6 !2015

Modernizing our JavaScript Stack

A. JavaScript Libraries

Flight

! Listing management tools

Hitting a Wall with Backbone&Handlebars Backbone & Handlebars approach falls apart as UI components become more dynamic. No data binding, so have to either: 1. Re-render whole view when model changes (slow, lose DOM state like focused fields). 2. Drop down to manual DOM manipulation.

Airbnb <3 React React makes it easier to build&maintain stateful UI components. React makes it easier to reason about data flow in your app.

B. Asset building

Sprockets Rails asset pipeline: manages JavaScripts, stylesheets, images, etc. Written by Ruby devs to solve problems of simple web apps.

JavaScript </3 Sprockets Doesn’t solve JavaScript dependency management: 1. Local dependencies (application code) 2. External dependencies (third-part libraries)

/* application.js */ //= require_tree . /* application.js */ ! //= require ./models/listing.js //= require ./collections/listings.js //= require_tree . What if one file depends on another? Bad: Order matters Bad: Objects attached to `window` Bad: Implicit dependencies Local dependencies

$ cp ~/Downloads/backbone.js app/assets/javascripts/vendor/ backbone-1.1.12.js /* application.js */ ! //= require vendor/backbone-1.1.12.js ... //= require_tree . What if I want to use Backbone? Bad: Manually download Bad: Manually versioning Bad: Implicit dependencies External dependencies

CommonJS&NPM to the rescue

/* collections/listings.js */ var Listing = require(‘../models/listing’); ! module.exports = ... Good: Explicit dependencies Good: Don’t worry about ordering Good: Objects not leaked to `window` Local dependencies

/* collections/listings.js */ var Listing = require(‘../models/listing’); var Backbone = require(‘backbone’); ! module.exports = Backbone.Collection.extend({ ... }); Good: Central management Good: Explicit dependencies External dependencies $ npm install --save backbone@1.1.2

Explicit Dependencies

Browserify* Use CommonJS syntax in client-side modules: `require` and `module.exports`. Package dependencies from NPM. Transforms. * or Webpack

Browserify Transforms Handlebars var template = require(‘./templates/user.hbs’); ! var html = template({name: “Spike”}); es2015 import Header from ‘./Header.jsx’; ! const numMonths = 36; ! let photos = users.map((user) => user.photo);

Airbnb&Isomorphic JavaScript

JavaScript code that can be shared between environments.

Client-side MVC Client Server Your app API

Client + server MVC Server Client Your app API

Performance Initial pageload speed. SEO* Crawlable single-page apps. Flexibility Run code anywhere. Maintainability Reduce code duplication.

Performance

Client-rendered app Download skeleton HTML User sees content Download JavaScript Fetch data from API Evaluate JavaScript Exacerbated on mobile: high latency, low bandwidth

Server-rendered app Download full HTML Download JavaScript User sees content Evaluate JavaScript

Rendr

Moving Away from Rendr at Airbnb

It was revolutionary to share code between client and server using Node.js…

10% 90% Rails Node.js …but too hard to share code between server and server— between Rails and Node.js. Long tail of features to rewrite in JavaScript: 1. CSRF tokens 2. Custom headers, i.e. CDN 3. Middleware 4. Application code

Do we rewrite everything in Node.js?

The single worst strategic mistake that any software company can make: ! Rewrite the code from scratch. Joel Spolsky

A New Approach to Isomorphic JavaScript at Airbnb

Browser. Rails. App.jsx Fetch JSON data Node.js.App.jsx

Mystique: Node.js rendering service for React components Allows us to render React components on the server from within Rails. Built on Iso, tiny utility for isomorphic bootstrapping of React components. https://github.com/goatslacker/iso

! https://www.airbnb.com/getaways/san-francisco A/B testing now

Thanks!! ! @spikebrehm @AirbnbNerds