Web Apps: Past & Future

17.11.2015

Michael Bromley

Gentics Software

Current Technology

Limitations & Problems

Solutions & Innovations

Increased scope & complexity

The Pre-JavaScript Period

  • Invention of the web: 1990

The Pre-JavaScript Period

Problems Solved

  • Websites possible

New Problems

  • Poor interactivity
  • Unresponsive UIs
  • No drop-down menus (!!)

The DHTML Period

  • May 1995: Brendan Eich creates JavaScript
  • November 1996: Netscape submit standard to Ecma.

The DHTML Period

The DHTML Period

Problems Solved

  • Better user experience
  • More interactive
  • Client-side logic (fewer network calls)

New Problems

  • Bad APIs (DOM)
  • Inconsistent APIs (DOM!) 
  • No async data

The jQuery & AJAX Period

  • Prototype.js: 2005
  • Dojo: 2005
  • jQuery: 2006
  • MooTools: 2006
  • YUI: 2006
  • Gmail: 2005
  • XmlHttpRequest Spec: 2006

The jQuery & AJAX Period

// native DOM API
if (el.classList)
  el.classList.contains(className);
else
  new RegExp('(^| )' + className 
    + '( |$)', 'gi').test(el.className);
// with jQuery
$(el).hasClass(className);

vs.

var request = new XMLHttpRequest();
request.open('GET', '/my/url', true);
request.onload = function() {
  if (request.status >= 200 && request.status < 400) {
    // Success!
    var data = JSON.parse(request.responseText);
  } else {
    // error response

  }
};
request.onerror = function() {
  // connection error of some sort
};
request.send();
$.getJSON('/my/url', function(data) {

});

vs.

The jQuery & AJAX Period

Problems Solved

  • Concise, intuitive DOM APIs
  • Fixes browser inconsistencies
  • AJAX = real web apps possible

New Problems

  • No code structure = spaghetti
  • Hidden coupling to DOM
  • Data being stored in DOM
  • Keeping model / UI in sync

Evolutionary Dead Ends

Evolutionary Dead Ends

Problems Solved

  • Features!

New Problems

  • Need plugins to work
  • Proprietary
  • Performance / resource usage
  • Poor security record

The SPA Revolution

  • Angular: 2009
  • Backbone: 2010
  • Knockout: 2010
  • Ember: 2011

The SPA Revolution

Problems Solved

  • Code structure (MVC, etc.)
  • Data-binding is trivial
  • Fully featured frameworks (routing, ajax, etc.) for entire app.

Current Technology

Limitations & Problems

Solutions & Innovations

Increased scope & complexity

The SPA Revolution

Today's Problems: Complexity

  • Managing state
  • Managing complex data flow
  • Managing concurrency & real-time apps
  • Managing huge code bases & teams
  • Keeping the app reliable and predictable
  • Mobile experience
  • SEO

Solutions?

  • RxJS
  • Bacon.js
  • Cycle.js
  • Immutable.js
  • Angular2
  • virtual-dom
  • universal javascript
  • Babel
  • Elm
  • ES6/2015
  • TypeScript
  • React
  • Flux
  • Redux
  • React Native
  • NativeScript
  • Meteor
  • Aurelia
  • Webpack
  • System.js
  • Ionic
  • etc.

Solutions!

  • Component-based architecture
  • One-way data-flow
  • Functional programming & immutability
  • Reactive programming
  • Modular rendering
  • Transpilation

Component Architecture

Component Architecture

App

Sidebar

Contacts

Menu

Contents

ChatWindow

Component Architecture

<App />

<Sidebar />

<Contents />

<Contacts />

<Menu />

<ChatWindow />

One-Way Data Flow

One-Way Data Flow

Parent Component

Child Component

Data

Callback

Callback(         )

Data

One-Way Data Flow

  • Allows efficient change detection
  • Allows a predictable order of execution
  • = Easier to understand the code.
  • = Less error-prone code, easier to debug

Advantages

One-Way Data Flow

Resources

 

Functional Programming

& Immutability

  • Style of programming
  • Simple functions composed together
  • Avoids mutation
  • Avoids side-effects

Functional Programming

& Immutability

  • Concise, declarative code
  • More robust code
  • More testable

Advantages

function square(x) {
    return x * x;
}

let a = [1, 2, 3, 4];

let b = a.map(square);

// b = [1, 4, 9, 16];

Functional Programming

& Immutability

Function Programming in Javascript (interactive tutorial)

http://reactivex.io/learnrx/​

Resources

Immutable.js: 

https://facebook.github.io/immutable-js/

Reactive Programming

  • Programming with async data streams

merge(a, b)

a

b

Reactive Programming

/* Get stock data somehow */
var source = getStockData();

source
  .filter(quote => quote.price > 30)

  .map(quote => quote.price)

  .forEach(price => {
    console.log('Prices higher than $30: $' + price);
  });

Reactive Programming

Advantages

  • Modern UIs fit with async streams
    • User input events
    • Real-time/web socket updates
  • Works well with Functional principles
    • Less state to manage
    • Terse, declarative code

Reactive Programming

Resources

Modular Rendering

Browser

JavaScript App

DOM (user interface)

Renders

Modular Rendering

Browser

JavaScript App

(core)

DOM (user interface)

Renders

JavaScript App

DOM renderer

Ready to render

Modular Rendering

Browser

JavaScript App (core)

DOM renderer

Server renderer

Server

Mobile native renderer

Mobile App

Modular Rendering

Resources

Transpilation

  • TypeScript
  • Dart
  • Elm
  • JSX
  • ClojureScript
  • CoffeeScript

Transpiler

(e.g. Babel)

JavaScript

Browser

Transpilation

Why Transpile?

  • Use the latest JS features today
  • Use any of over 100 other languages
  • Features: types, decorators, immutability etc.

Transpilation

  • Adds a type system to JavaScript
  • Much improved tooling
  • Static type checking
  • Catches bugs before run-time

Transpilation

Resources

 

 

Summary

  • Our job is to solve problems
  • ...continually
  • Today's problems are big & complex
  • There are many solutions
  • Always keep learning

Thank You!

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