Modern Web 2015

  • JS - 20y
  • D3
  • React

JavaScript at 20 Years

Brendan Eich

  • creating JS in 10 days (1995)

Java was the big Web VM

 

JavaScript was "little brother"

Java is typed (or statically typed) and has mostly-typed bytecode

 

JS is untyped (or dynamically typed)

Much progress

JS is untyped (dynamically typed), 

 

asm.js is typed "bytecode" with deterministic performance

demo

asm.js( with Unity)

http://beta.unity3d.com/jonas/DT2/

class vector {
  constructor(n) { this.arr = new Int32Array(n); }
  sum() {
    let la = this.arr;
    let S = 0;
    for (let i = la.length|0; (i=(i-1)|0) >= 0;)
      S = (S + la[i|0])|0;
    return S;
  }
}
  • class
  • constructor
  • let
  • Int32Array
  • i|0

asm.js & ES6

A selective tour of ES6

let square = x => x * x;
square(4);     // 16

ES6/2015, ES7/2016, ES8...

Compiling to JS is not new

Always bet on JS

  • First they said JS couldn't be useful for building "rich Internet apps"

  • Then they said it could't be fast.

  • Then they said it could't be fixed.

  • Then it couldn't do multicore/GPU

  • Wrong every time!

D3

Data-Driven Documents

http://d3js.org/

D3.js is a JavaScript library for manipulating documents based on data. D3 helps you bring data to life using HTML, SVG, and CSS. 

how to plot a
bar chart in HTML

  var dataset = [25, 50, 75, 100, 125];

<div style="display:inline-block;
            width: 20px;
            height:75px;
            background-color:teal;">
</div>
<div style="display:inline-block;
            width: 20px;
            height:75px;
            background-color:teal;">
</div>

<div style="display:inline-block;
            width: 20px;
            height:75px;
            background-color:teal;">
</div>

<div style="display:inline-block;
            width: 20px;
            height:75px;
            background-color:teal;">
</div>

<div style="display:inline-block;
            width: 20px;
            height:75px;
            background-color:teal;">
</div>

<div style="display:inline-block;
            width: 20px;
            height:75px;
            background-color:teal;">
</div>

<div class='bar'></div>
<div class='bar'></div>
<div class='bar'></div>
<div class='bar'></div>
<div class='bar'></div>
div.bar {
    display:inline-block;
    width: 20px;
    height:75px;
    background-color:teal;
}
  var dataset = [25, 50, 75, 100, 125];
<div class='bar' style="height:25px;"></div>
<div class='bar' style="height:50px;"></div>
<div class='bar' style="height:75px;"></div>
<div class='bar' style="height:100px;"></div>
<div class='bar' style="height:125px;"></div>
div.bar {
    display:inline-block;
    width: 20px;
    height:75px;
    background-color:teal;
}
div.bar {
    display:inline-block;
    width: 20px;
    height:75px;
    background-color:teal;
}
  var dataset = [25, 50, 75, 100, 125];

// jQuery ************************

  $.each(dataset, function(key,val){
      $('<div/>',{
          class:"bar",
          height:val
      }).appendTo('body');
  });
  var dataset = [25, 50, 75, 100, 125];

// jQuery ************************

  $.each(dataset, function(key,val){
      $('<div/>',{
          class:"bar",
          height:val
      }).appendTo('body');
  });

// D3 ****************************

  d3.select('body').selectAll('div')
      .data(dataset)
      .enter();
      .append('div')
      .attr('class','bar')
      .style('height',function(val){
          return val + "px"; 
      });
div.bar {
    display:inline-block;
    width: 20px;
    height:75px;
    background-color:teal;
}
  d3.select('body').selectAll('div')
      .data(dataset)
      .enter();
      .append('div')
      .attr('class','bar')
      .style('height',function(val){
          return val + "px"; 
      });
  d3.select('svg').selectAll('circle')
      .data(dataset)
      .enter();
      .append('circle')
      .attr('fill','teal')
      .attr("r", function(val) {
        return val;
      });

<svg>

<canvas>

HTML 5

</html>
    <head>
        <title>SVG</title>
    </head>
    <body>
        <svg width="500" height="50">
            <circle cx="25" cy="25" r="5" fill="teal"></circle>
            <circle cx="75" cy="25" r="10" fill="teal"></circle>
            <circle cx="125" cy="25" r="15" fill="teal"></circle>
            <circle cx="175" cy="25" r="20" fill="teal"></circle>
            <circle cx="225" cy="25" r="25" fill="teal"></circle>
        </svg>
    </body>
</html>
</html>
    <head>
        <title>CANVAS</title>
    </head>
    <body>
        <canvas />
    </body>
</html>
SVG Canvas
以形狀為主 以像素為主 (動態 .png)
多重圖形元素 (會成為 DOM 的一部分) 單一 HTML 元素
可以透過指令碼與 CSS 修改 只能透過指令碼修改
事件模型/使用者互動抽象化 (矩形、路徑) 事件模型/使用者互動很精確 (x,y)
物件較少 (<10k) 和/或表面較大時的效能較佳 表面較小和/或物件較多 (>10k) 時的效能較佳

林口精品牆 -- 戰情室

http://ds.advantech.com.tw/StrategyDashboard/

http://fhy.wra.gov.tw/ReservoirPage_2011/StorageCapacity.aspx

http://water.taiwanstat.com/

http://muyueh.com/30/xinzhu_traffic/

http://www.nytimes.com/interactive/2012/09/06/us/politics/convention-word-counts.html

React

A JAVASCRIPT LIBRARY FOR BUILDING USER INTERFACES

  • Facebook 於 2013 年中開源

  • React 內建 VDOM 是輕量的顯示元件

  • 類似MVC但不是MVC，自創了Flux流程

Intro

  • 簡單易學、一天入門 (講者說的，而且他上次說兩天入門)

  • 思維模式單純

  • 強大防呆、結構單純、不易出錯

  • 頁面效能優越

  • server-rendering, Isomorphic for SEO, faster response

<!DOCTYPE html>
<html>
  <head>
    <script src="build/react.js"></script>
    <script src="build/JSXTransformer.js">
    </script>
  </head>

  <body>

    <div id="example"></div>

    <script type="text/jsx">
      React.render(
        <h1>Hello, world!</h1>,
        document.getElementById('example')
      );
    </script>

  </body>
</html>
<!DOCTYPE html>
<html>
  <head>
    <script src="build/react.js"></script>
    <script src="build/JSXTransformer.js">
    </script>
  </head>

  <body>

    <div id="example">
        <h1>Hello, world!</h1>
    </div>

  </body>
</html>

Code

View in Browser

      React.render(
        <h1>Hello, world!</h1>,
        document.getElementById('example');
      );
      React.render(
          React.createElement('h1', null, 'Hello, world!'),
          document.getElementById('example')
      );

JSX

JavaScript

  • single source of truth
    單向資料流
     

  • thinking in component
    元件化思考
     

  • always redraw (VDOM)
    一律重繪

Core Concept

single source of truth ( 單向資料流 )

 

  • FilterableProductTable (orange): contains the entirety of the example

  • SearchBar (blue): receives all user input

  • ProductTable (green): displays and filters the data collection based on user input

  • ProductCategoryRow (turquoise): displays a heading for each category

  • ProductRow (red): displays a row for each product

<FilterableProductTable>
   <SearchBar/>
   <ProductTable>  
       <ProductCategoryRow/>
       <ProductRow/>
   </ProductTable>
</FilterableProductTable>

https://jsfiddle.net/reactjs/yun1vgqb/light/

https://jsfiddle.net/reactjs/n47gckhr/light/

thinking in component ( 元件化思考 )

How about  React work with jQuery ?

always redraw (VDOM) 一律重繪

Since React has VDOM(virtual DOM),  
we don't need jQuery for DOM case.

React Native

  • 2015 年 1 月於 React Conf 推出

  • 讓所有網頁開發者可製作 native mobile app

  • 支援 iOS 與 Android 
    (iOS 已於2015年4月release, Android預計10月)

  • 不使使用Webview 與 HTML

  • 採用 javascript/html/css 等熟悉技術開發

  • 懂 react 即可開發

  • 開發一次，可支持不同 drawing backend

Facebook group

Always bet on JS

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