Architecting resilient front-ends, jQuery UK, 2015

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RESILIENT FRONT-ENDS @andyhume jQuery UK, 2015 ARCHITECTING

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waiting for fonts.com

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http:// Unreliable network

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http:// Resilient web

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Progressive enhancement http://www.flickr.com/photos/8040811@N06/3167877765 Progressive enhancement

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Content THREE STAGES Enhancement Leftovers

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Content THREE STAGES Enhancement Leftovers

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Content THREE STAGES Enhancement Leftovers

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Content THREE STAGES Enhancement Leftovers

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Content Enhancement Leftovers

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Content Enhancement Leftovers

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Time to screen Key performance metric Aiming for 1s on mobile Understand the network Understand the browser

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp SSL Handshake

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp HTTP Redirect SSL Handshake

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp HTTP Redirect SSL Handshake

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp HTTP Redirect SSL Handshake

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp HTTP Redirect SSL Handshake

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Time to screen: The network DNS lookup TCP connect HTTP request Server time HTTP resp HTTP Redirect SSL Handshake

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Eliminate redirects Flush the document early Prefetch DNS But mostly, eliminate redirects Time to screen: The network

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Time to screen: The browser Single threaded event loop 1. Construct DOM tree from HTML 2. Construct render tree from DOM tree and stylesheets 3. Layout paint

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Time to screen: Start render HTML parser DOM tree Layout Paint Render tree

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Time to screen: Start render HTML parser DOM tree Layout Paint Render tree

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Time to screen: Start render HTML parser DOM tree Layout Paint Render tree

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Time to screen: Start render HTML parser DOM tree Layout Paint Render tree

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Blocking: remote script

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Blocking: inline script waiting on remote CSS var rules = window.styleSheets[0].cssRules;

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Blocking: remote script (solution 1)

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Blocking: remote script (solution 2) var script = document.createElement('script'); script.src = "app.js"; document.head.appendChild(script);

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Blocking: remote script (solution 2) var script = document.createElement('script'); script.src = "app.js"; document.head.appendChild(script); HIDDEN FROM PRE-PARSER!

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Blocking: remote script (solution 3)

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Time to screen: Start render HTML parser DOM tree Layout Paint Render tree

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Time to screen: Start render HTML parser DOM tree Layout Paint Render tree

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Time to screen: Start render HTML parser DOM tree Layout Paint Render tree

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Time to screen: Start render HTML parser DOM tree Layout Paint Render tree

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Blocking: fetching stylesheets

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Blocking: fetching stylesheets (solution) // Core styles in the head of the document. body { background: grey; color: #3A2FDE; }

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Blocking: critical CSS generators https://github.com/pocketjoso/penthouse http://jonassebastianohlsson.com/ criticalpathcssgenerator/ https://github.com/filamentgroup/criticalcss

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Recap: What blocks render? Remote scripts that need to be executed synchronously Inline script waiting on stylesheet fetch Stylesheet fetch for relevant media type/query

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Recap: Fault isolation …or swimlaning Avoid synchronous dependencies Uptime is not binary

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Blocking web fonts

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Blocking web fonts

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Blocking web fonts HTML CSS FONT FONT FONT START RENDER

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Blocking web fonts HTML CSS FONT FONT FONT START RENDER TEXT RENDER

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Blocking web fonts HTML CSS FONT FONT FONT START RENDER TEXT RENDER

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Blocking web fonts FALLBACK BLOCKING BLOCKING + TIMEOUT Internet Explorer Safari Mobile Safari Chrome Opera (Blink) Firefox Opera (Presto)

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Web font loader Provide control over font loading Remove fonts from the critical path Make cross-browser behaviour consistent

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Web font loader

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Web font loader

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Web font loader var WebFontConfig = { custom: { families: ['Clarendon', 'Clarendon Bold'], urls: ['/myfonts.css'] } };

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Web font loader

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Web font loader h1 { font-family: georgia, serif; } .clarendon-loaded h1 { font-family: Clarendon, georgia, serif; }

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CSS Font Loading Module document.fonts.load(‘Clarendon’).then(function () { document.documentElement.className += ‘clarendon-loaded'; } h1 { font-family: georgia, serif; } .clarendon-loaded h1 { font-family: Clarendon, georgia, serif; }

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http://

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http://www.webpagetest.org/result/130908_K2_796/ Median of nine test runs

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http://www.webpagetest.org/result/130908_K2_796/ Median of nine test runs iPhone 4, iOS 5.1

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http://www.webpagetest.org/result/130908_K2_796/ Median of nine test runs 3G (1.6Mps, 300ms RTT) iPhone 4, iOS 5.1

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Thank-you! lanyrd.com/sddxxk @andyhume Creative Commons Licensed Attribution, Non-Commercial, Share Alike cc