FROM HACKER 
 TO PROGRAMMER Developing with Webpack,Babel, and React @josephj6802 1 Oct 2015 

Hacker? Probably Worse… Inefficient or dirty works Sadly especially for front-end code 

Tag Soup in JS if (inlineTileOptions['show_sharing'] === "1") { // Inline Sharing Buttons var tileSharing = $('

Tag Soup in View Difficult to read and maintain 

CSS/JS Tags Impossible to remove no longer used scripts No Dependency 

Environments Too many environments Feature Detection Browser Support Hacks Responsive 

Copy Paste fluid.js fluid-horizontal.js base_waterfall.js base_carousel.js auto.js main.js carousel.js slideshow.js base_billboard.js base_feed.js base_slideshow.js 80% duplicated code (~1500 lines) * 11 Widget Code Once we start, it’s difficult to refactor 

Prototype-based Class Everyone has their own implementation Stackla.createClass(); Widget = (function () {})(); function StacklaWidgetNode() {} 

Global Variables Global variables and function names are an incredibly bad idea. The reason is that every JavaScript file included in the page runs in the same scope. If you have global variables or functions in your code, scripts included after yours that contain the same variable and function names will overwrite your variables/functions. 

Stoyan Stefanov The few man-hours spent writing the code initially end up in man-weeks spent reading it. Getting Worse 

Eliminate the hacking As a developer, we always seek for good methodologies, patterns, or better technologies to make our code to be maintained easier. “A bug could be fixed within 10 mins by a newbie, but a good developer is willing spend 4 hours to make it better.” 

Happy Developer! when using right tools & code become less messy 

Universal loader for all static assets Ability to write next-generation JS Lead and change the world of front-end app development Foundation Accelerator App New Web Development Stacks 

Universal Loader Foundation 

JS Module Before Webpack AMD Make use of global variables Ease of define dependencies No dependencies Load modules asynchronously No compile needed by default Ease of define dependencies Always need to compile Synchronous loading by a single file (via global) define(['./a', './b'], function (a, b) {! }); var Acl = require('js/acl/acl.js'); 

Package Management CSS Preproccessors JS Module Loaders JS Transpiler Build Tools 

https://www.flickr.com/photos/juhansonin/3141561416/ You’ll need… Not fun… A lot of plug-ins and some hacks.. 

Package Management CSS Preproccessors JS Module Loaders JS Transpiler Build Tools less-loader sass-loader coffee-loader ts-loader Support ALL JS STATIC 
 Modules Webpack Dev Server 

// app/media/js/admin/terms/term-manage.jsx! ! 'use strict';! ! var React = require('react'),! $ = require('jquery'),! LogMixin = require('common/log-mixin'),! TermPanel = require('./term-panel'),! TermList = require('./term-list'),! History = require('exports?window.History!history.js/native.history'),! queryString = require('query-string'),! Cookies = require('js-cookie');! ! module.exports = {! // ...! }; Define Dependencies app/vendor/webpack/node_modules/ app/media/js/ app/media/components/ 

var History = require('exports?window.History!history.js/native.history');! ! History.Adapter.bind(window, 'statechange', that.handleHistoryChange); Global Module require('history.js/native.history');! ! window.History.Adapter.bind(window, 'statechange', that.handleHistoryChange); Not Good Better exports?window.History!history.js/native.history loader loader options (query) separator module path 

JS Transpilers var Tagla = require('coffee!./tagla.coffee'); var Stepper = require('ts!./stepper.js'); 

CSS Preprocessors require('!style!css!sass!admin/acl/acl.scss'); require('!style!css!less!bootstrap/nav.less'); 

CSS Preprocessors Wait! Are you writing CSS in JS? require('!style!css!sass!admin/acl/acl.scss'); app/media/js/admin/acl/acl.js • The stylesheet will be injected into HTML with tag • The images inside will be converted to Data URIs. Define dependencies between JS and CSS 

Code Splitting fluid-embed.js
 (required) when layout = portrait or landscape Load extra assets conditionally lightbox.js
 (optional) 

Dev Server Incremental build instead of full build 

• Module Loader / Dependencies • Ability to load all kinds of assets • High performance • Often replaces grunt or gulp 

Using the future of JS, Today! Accelerator 

Package Management CSS Preproccessors JS Module Loaders JS Transpiler Build Tools sass-loader coffee-loader ts-loader Support ALL Modules Webpack Dev Server babel-loader less-loader 

Why Babel? All transpilers are trying to *fix* JavaScript language These transpilers have obvious influence on the ES6/ES2015 standard. However browser support is not ready yet 

Why Babel? Babel is another transpiler which let you to use latest JS Babel keeps sync with ECMAScript Ability to customise the stage or options you want use. 

var: Function-scoped Let & Const function f() {! var obj = {a: 1, b: 2, c: 3}; ! for (var i in obj) {! // okay! console.log(i); ! } ! // okay ! console.log(i);! }! f(); let: Block-scoped function f() {! var obj = {a: 1, b: 2, c: 3}; ! for (let i in obj) {! // okay! console.log(i); ! } ! // error - i is undefined ! console.log(i);! }! f(); const: Block-scoped function a() {! const DURATION = 100;! {! // output 100! console.log(DURATION);! }! }! ! function b() {! const DURATION = 100;! {! // error "DURATION" is read-only! DURATION = 200;! } ! }! ! function c() {! const DURATION = 100;! {! // ok ! const DURATION = 200;! console.log(DURATION); // output 200! } ! }! Single-assigment 

`Template String` // This is what I prefer to do! var list = ['

',! '
• Buy Milk
',! '
• Be kind to Pandas
',! '
• Forget about Dre
',! '

'].join(''); ES5 // This doesn't work! var list = '

!
• Buy Milk
!
• Be kind to Pandas
!
• Forget about Dre
!

';! // This does, but urgh… ! var list = '

\!
• Buy Milk
\!
• Be kind to Pandas
\!
• Forget about Dre
\!

'; // This is the most common way, and urgh, too…! var list = '

' +! '
• Buy Milk
' +! '
• Be kind to Pandas
' +! '
• Forget about Dre
' +! '

'; ES6 // This works!! var list = `

!
• Buy Milk
!
• Be kind to Pandas
!
• Forget about Dre
!

`;! http://christianheilmann.com/2015/08/28/es6-for-now-template-strings/ 

`Template String` ES5 - String + Variables var avatar = ''; var avatar = ``; ES6 - String + Variables The ${} construct can take any JS expression that returns a value 

class Widget extends Stackla.Base {! constructor(options) {! super(options);! ! this.domain = options.domain || null;! this.list_url = `/widget/api/${this.guid}! ?filter_id=${this.filter_id}! &domain=${this.domain}! &page=1! &ttl=1`; ! }! render(el) {! super.render();! }! static getInstances() {! // ...! }! } Classes ES6 - Single convenient declarative form 

Module https://babeljs.io/docs/learn-es2015/#modules 

Arrow https://babeljs.io/docs/learn-es2015/#arrows-and-lexical-this 

Summary • Unlike CoffeeScript, it’s something you must learn and use in the future. • Just like PHP4 v.s. PHP5 • Makes my code more legible (ex. class) • develop much faster (ex. less vague, type safety) 

App Build UI & APPs 

Why so Popular? Google Trend http://reactkungfu.com/2015/07/big-names-using-react-js/ Big Brands using React.js 

• Rethink best practices • JSX - Template in JavaScript? • CSS in JS - Inline style in JavaScript? • Easy to learn • Embracing Functional Programming • One-way data flow model • Impacting different areas • ImmutableJS, GraphQL Why so Popular? 

Package Management CSS Preproccessors JS Module Loaders JS Transpiler Build Tools sass-loader Support ALL Modules Webpack Dev Server babel-loader less-loader built-in support for React JSX 

Abstraction Delete Button New Way Using Class Names Using React.js Old Way Legible & Less Guessing 

f Delete button.jsx exports default class Button extends React.Component {! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! }; this.props.size this.props.kind this.props.solid this.props.children Load CSS Just CSS class name manipulation render() is the only required method in React component import React from 'react';! import cx from 'classnames';! import 'stackla-uikit/scss/_button'; render() {! let that = this,! props = that.props,! className,! node;! ! className = cx('st-btn',`st-btn-${kind}`, {! 'st-btn-disabled': props.disabled,! 'st-btn-solid': props.solid,! 'st-btn-md': (props.size === 'medium'),! 'st-btn-sm': (props.size === 'small'),! 'st-active': props.active,! }, props.className);! ! return {props.children}! } The calculated class names Properties 

f State import React from 'react';! import Button from './button';! const data = [! {text: 'Danger', kind: 'danger', size: 'large', solid: false, active: true},! {text: 'Success', kind: 'success', size: 'medium', disabled: true, solid: true},! {text: 'Info', kind: 'info', disabled: true, solid: true},! {text: 'Default', kind: 'default', size: 'large', disabled: true, active: false}! ];! exports default class App extends React.Component {! constructor() {! this.offset = 0;! }! componentDidMount() {! setInterval(() => {! this.offset = (data.length >= this.offset + 1) ? 0 : this.offset + 1;! this.setState(data[this.offset]);! }, 500);! }! render() {! let state = this.state;! return ! ! {state.text}! ;! }! }; app.jsx React.render(, document.getElementById('app')); Mockup Data Whenever the state changes, the render() will be invoked For Button component, whenever my property changes, the Button#render() will be invoked 

Only outmost component is stateful Others are stateless, only accept properties 

Only outmost component is stateful Others are stateless, only accept properties WidgetsNew StyleChooser StylePreview widgetTypes selectedWidget render() render() render() widgetTypes selectedWidget Top-down Rendering JSX diffs and apply changes to DOM 

UI = f(state) Update UI by changing state object Philosophy 

Sebastian Markbåge DOM as a Second-class Citizen https://www.youtube.com/watch?v=Zemce4Y1Y-A 

A Tool to Build Our Toolbox Only ourselves knows what we want, picking up technologies for right abstraction is crucial. No single library can fulfil our need. Can we build an app without a single DOM element? 

Abstraction for Different Targets • React.js in Browser • JSX ➡ DOM • react-canvas in Browser • JSX ➡ Canvas • react-isomorphics in Server • JSX ➡ HTML • react-native in iOS • JSX ➡ UIKit • react-native in Android • JSX ➡ android.view 

Ambitious Abstraction In Browser, React/JSX relies on slow DOM API. Goal Ask WebGL/GPU to use React directly Now 

➡ ➡ ➡ ➡ ➡ Getting Better & Mature ➡ ➡ ➡ ! ! ! 

➡ ➡ ➡ ➡ ➡ Getting Better & Mature ➡ ➡ ➡ ! ! ! Will these tools go out of fashion in the following 18 months? POSSIBLY! However, everything is becoming 
 more mature and future-compatible We developers just need to choose right tools to do improvements 

Feel blessed with I feel much more solid to write UI now. Not a hacker but a programmer! $IFFST