From Hacker to Programmer (w/ Webpack, Babel and React)

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 = $('<div class="tile-sharing"><a class="tile-sharing-expand js-expand-tile-
sharing stackla-icon-share" onclick="Widget.expandInlineSharingTool(th
var tileShareButtons = $('<ul class="tile-sharing-expanded"></ul>');
tileSharing.append(tileShareButtons);
item.append(tileSharing);
!
var shareText = t['share_text'] ? t['share_text'].replace(/["']/g, '$&') : '';
!
if (t['source'] != 'facebook') {
tileShareButtons.append('<li><a data-tile-id="' + t['_id'] + '" class="tile-share-button
facebook" title="Share via Facebook" onclick="Widget.facebookShare(th
}
!
twitter" title="Share via Twitter" onclick="Widget.twitterShare(this)"><d
!
if (t['image']) {
pinterest" title="Share via Pinterest" onclick="Widget.pinterestShare
}
!
tileShareButtons.append('<li><a data-tile-id="' + t['_id'] + '" class="tile-share-button gplus"
title="Share" onclick="Widget.googleShare(this)"><div class="share
!
tileShareButtons.append('<li><a data-tile-id="' + t['_id'] + '" class="tile-share-button email"
title="Email a friend" onclick="Widget.emailShare(this)"><div clas
!
!
}
Difﬁcult to read and maintain

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

JS Module Before Webpack
AMD
<script/>
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 <style> 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() {!
{!
// error "DURATION" is read-only!
DURATION = 200;!
} !
}!
!
function c() {!
{!
// ok !
console.log(DURATION); // output 200!
} !
}!
Single-assigment

`Template String`
// This is what I prefer to do!
var list = ['<ul>',!
' <li>Buy Milk</li>',!
' <li>Be kind to Pandas</li>',!
' <li>Forget about Dre</li>',!
'</ul>'].join('');
ES5
// This doesn't work!
var list = '<ul>!
<li>Buy Milk</li>!
<li>Be kind to Pandas</li>!
<li>Forget about Dre</li>!
</ul>';!
// This does, but urgh… !
var list = '<ul>!
<li>Buy Milk</li>!
</ul>';
// This is the most common way, and urgh, too…!
var list = '<ul>' +!
' <li>Buy Milk</li>' +!
' <li>Be kind to Pandas</li>' +!
' <li>Forget about Dre</li>' +!
'</ul>';
ES6
// This works!!
var list = `<ul>!
<li>Buy Milk</li>!
</ul>`;!
http://christianheilmann.com/2015/08/28/es6-for-now-template-strings/

`Template String`
ES5 - String + Variables
var avatar = '<div class="avatar">' +!
' <a href="' + avatarLink + '" target="_blank" class="avatar-profile">' +!
' <div class="avatar-place-holder">' +!
' <img src="/media/images/avatar-mask.png" alt="' + avatarAltText + '" />' +!
' </div>' +!
' <img src="' + getAvatarUrl(t.avatar, t.source) + '" alt="' + avatarAltText + '" />' +!
' </a>' +!
'</div>';
var avatar = `<div class="avatar">!
<a href="${avatarLink}" target="_blank" class="avatar-profile">!
<div class="avatar-place-holder">!
<img src="/media/images/avatar-mask.png" alt="${avatarAltText}" />!
</div>!
<img src="${getAvatarUrl(t.avatar, t.source)}" alt="${avatarAltText}" />!
</a>!
</div>`;
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)

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
<button class="st-btn !
st-btn-danger !
st-btn-solid !
st-btn-md”>!
Delete!
</button>
<Button kind="danger" !
size="medium" !
solid>Delete</Button>
Button
New Way
Using Class Names
Using React.js
Old Way
Legible & Less Guessing

f
<Button kind="danger" size="large" solid>Delete</Button>
button.jsx
exports default class Button extends React.Component {!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
};
this.props.sizethis.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 <button {...props} className={className}>{props.children}</button>!
}
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 !
<Button !
kind={state.kind} !
size={state.size} !
solid={state.solid} !
active={state.active}>!
{state.text}!
</Button>;!
}!
};
app.jsx
React.render(<App>, 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

<StyleChooser/>
<StylePreview/>
<Breadcrumbs/>
<Panel/>
<WidgetsNew/>
<Button/>
<Button/>
Only outmost component is stateful
Others are stateless,
only accept properties

<StyleChooser/>
<StylePreview/>
<Breadcrumbs/>
<Panel/>
<WidgetsNew/>
<Button/>
<Button/>
Only outmost component is stateful
Others are stateless,
only accept properties
WidgetsNew
StyleChooser StylePreview
widgetTypes selectedWidget
render()
render() render()
<StyleChooser widgetTypes= />widgetTypes <StyleChooser selectedWidget= />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

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Getting Better & Mature
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Getting Better & Mature
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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!
Cheers!

From Hacker to Programmer (w/ Webpack, Babel and React)

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