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About myself●Front-End Engineer at Yandex
●Developer of Yandex.Taxi and Yandex.Mobile
● JavaScript Teacher
●Blogger
02
ComponentsNow!
Mikhail Davydov
MetaRefresh, 15 Feb 2014
Code libraries
Code libraries● jQuery — fixes DOM
●Underscore — fills ECMAScript 3-5 gap
●Backbone — brings MV*
●They are created to fix Web
For some historical reasons many good tools are libraries.
The DOM is a Mess 2009
06
Libraries are everywhere
Libraries are big●Heavy
–jQuery 2.0.3 — 230K (unpacked)
●Hard to understand
–Cyclomatic complexity of $.ajax — 43
●Too powerful
–$.ajax, $.animate, _08
Libraries are tightly coupled●Hard to get a small part
–$.Deferred, $.ajax
–_.template
●Manual extraction
●Their modules don't help much
09
Dependencies management●Dependency on jQuery
●Libraries require libraries
–Backbone+jQuery+Underscore
●Manual dependencies management
–Bower and Npm are lifesavers
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Web is fixed*
Critical DOM APIs●querySelector
●CSS3 Selectors*
●Web Storage (localStorage)
●Cross-Origin Resource Sharing*
* fully with polyfills
Can I Use
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Polyfills can fix the rest●CSS3 Selectors (slow, not recommended)
●Cross-Origin Resource Sharing
●HTML5 Elements
●ECMAScript 5
HTML5 Please polyfills
15
Mobile
Mobile Growth
Why do we uselibraries?
Components
Simple
Components are simple●Lightweight
–dom — 28K, 3K self (unpacked)
●Single responsibility & KISS Principle
●Easy to understand
–Maintain
–Write tests21
Standalone
Components are standalone●Contain all dependencies
–Most of them are external
●Easy to reuse
– bower i name
– npm i name
● It is simple to use a part23
Isolated
Components are isolated●Do not interfere with others
–Scoped CSS
–Flexible layout
–No globals leak
●Have restricted access to others
– require()
25
WebComponents● Idea of Custom HTML Elements
●API/Framework
–Shadow DOM (Encapsulation)
–HTML Imports & Templates
–Template Binding
Web components and the future of web development from MR 201327
WebComponents in 2014HTML Templates
Shadow DOM
Custom Elements
HTML Imports
It is possible to polyfill others using Polymer.
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Alternatives for these APIsWebComponents API Alternative
Custom Elements Component engines
Shadow DOM BEM Methodology
HTML Templates Template engines
HTML Imports Build tools
Scoped CSS BEM or OOCSS
Template Binding Data binding
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Component engines●X-Tag
● jQuery UI Widgets
●Dojo Widgets
●React
●bem-tools
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BEM briefly●Avoid CSS cascade
●Block — Custom Element
●Element — Shadow DOM
●Modifier — Component State
Maintainable frontend development with BEM from MR 2013
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.tab-panel — Block
.tab-panel__tab — Element
.tab-panel__tab_state_active
Let's build theComponent!
Keep in mind that●Component is Simple
–KISS
●Component is Standalone
–Dependencies
●Component is Isolated
–Layout, CSS, JS36
Package file
Package file is the contract// bower.json
{
"name""name": "my-share""my-share",
"version""version": "1.0.0""1.0.0",
"main""main": ["my-share.js""my-share.js"]
}
Bower and format of bower.json
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HTML Layout
Private HTML Layout<!-- my-share.html -->
<aa hrefhref=""{{ href }}{{ href }}"" classclass="my-share""my-share">
<imgimg srcsrc=""{{ icon }}{{ icon }}"" classclass="my-share__icon""my-share__icon"/>
<spanspan classclass="my-share__label""my-share__label">{{ label }}</spanspan>
</aa>
This template is written using BEM Methodology.
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Interface
Interface<aa classclass="my-share""my-share"
data-href="{{ href }}"
data-icon="{{ icon }}"
>{{ label }}</aa>
This interface is similar to the WebComponents.
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WebComponents for comparison<my-sharemy-share
href="{{ href }}"
icon="{{ icon }}"
>{{ label }}</my-sharemy-share>
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CSS of Component..my-sharemy-share {}
.mymy-share__icon {
vertical-alignvertical-align: middle;middle;
heightheight: 16px;16px;
}
.mymy-share__label {
padding-leftpadding-left: 5px;5px;
}
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CSS of WebComponentmy-share {}
.icon {
vertical-alignvertical-align: middle;middle;
heightheight: 16px;16px;
}
.label {
padding-leftpadding-left: 5px;5px;
}
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CSS is isolated●WebComponent — DOM API
– <style scoped>
●BEM
–Avoid CSS cascade
–Naming conventions .block__element
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Dependencies
External dependencies// bower.json
"dependencies""dependencies": {
"tpl""tpl": "azproduction/lodash-template""azproduction/lodash-template",
"domify""domify": "component/domify""component/domify",
"decl""decl": "azproduction/decl""azproduction/decl"
}
Declare all external dependencies.
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Component relations// my-share.js
varvar tpl = require('tpl''tpl'),
decl = require('decl''decl'),
domify = require('domify''domify');
varvar html = require('templates/my-share''templates/my-share'),
template = tpl(html);
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Component logicfunctionfunction MyShare(el) {
thisthis.options = thisthis.collectOptions(el);
thisthis.el = thisthis.render();
thisthis.delegateEvents();
thisthis.replaceElement(el);
}
decl('.my-share''.my-share', MyShare);
module.exports = MyShare;
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JavaScript is isolated●CommonJS/Modules
–No globals leak
–It asks for requirements
–It provides resources
●AMD can be used too
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Assemble
Assemble component●Resolve all requirements
●Compile
–styles, scripts, templates
●Assemble scripts and templates
●Concatenate styles
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Component build tools●bem-tools
●Component
●Browserify
●LMD
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Using my-share Component<aa classclass="my-share""my-share" ......>Tweet</aa>
<linklink relrel="stylesheet""stylesheet" hrefhref=""my-share.cssmy-share.css""/>
<scriptscript srcsrc=""my-share.jsmy-share.js""></scriptscript>
Compare with WebComponents.
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Using my-share WebComponent<my-sharemy-share ......>Tweet</my-sharemy-share>
<linklink relrel="import""import" hrefhref=""my-share.htmlmy-share.html""/>
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Tweet
Live example
57
Conclusion●Web is Fixed, Mobile is Growing
●Libraries are big and clumsy
●WebComponents == API
●Write and use Components
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Components Now!
Mikhail Davydov
@azproduction
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Useful resources●Code of my-share
●You might not need jQuery
●BEM Methodology
●Web Components
●Polymer Project
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Sources of images● minecraft.gamepedia.com/Blocks
● fr.fotopedia.com/wiki/Bibliothèque#!/items/flickr-6899137527
● www.planetminecraft.com/project/minecraft-site/
● investments.academic.ru/1513/Форвардный_контракт
● frozen-lama.deviantart.com/art/Minecraft-Compound-Door-209872466
● www.postandcourier.com/article/20120620/pc1002/120629985
● isintu.com/features/responsive-design/
● nicolaijuhler.wordpress.com/
● r3c0nic.deviantart.com/art/minecraft-Blueprint-293455933
● ru-wallp.com/view/1542/
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