AngularJS

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AngularJS
AngularJS logo
Developer(s) Brat Tech LLC, Google and community.
Initial release 2009 (2009)
Stable release 1.2.21 / July 25, 2014; 5 days ago (2014-07-25)
Development status Active
Written in JavaScript
Operating system Cross-platform
Size 104 KiB production
760 KiB development
Type JavaScript library
License MIT License
Website angularjs.org

AngularJS is an open-source web application framework, maintained by Google and community, that assists with creating single-page applications, one-page web applications that only require HTML, CSS, and JavaScript on the client side. Its goal is to augment web applications with model–view–controller (MVC) capability, in an effort to make both development and testing easier.

The library reads in HTML that contains additional custom tag attributes; it then obeys the directives in those custom attributes, and binds input or output parts of the page to a model represented by standard JavaScript variables. The values of those JavaScript variables can be manually set, or retrieved from static or dynamic JSON resources.

Philosophy[edit]

AngularJS is built around the belief that declarative programming should be used for building user interfaces and wiring software components, while imperative programming is excellent for expressing business logic.[1] The framework adapts and extends traditional HTML to better serve dynamic content through two-way data-binding that allows for the automatic synchronization of models and views. As a result, AngularJS de-emphasizes DOM manipulation and improves testability & performance.

Design goals:

  • Decouple DOM manipulation from application logic. This improves the testability of the code.
  • Regard application testing as equal in importance to application writing. Testing difficulty is dramatically affected by the way the code is structured.
  • Decouple the client side of an application from the server side. This allows development work to progress in parallel, and allows for reuse of both sides.
  • Guide developers through the entire journey of building an application: from designing the UI, through writing the business logic, to testing.

Angular follows the MVC pattern of software engineering and encourages loose coupling between presentation, data, and logic components. Using dependency injection, Angular brings traditional server-side services, such as view-dependent controllers, to client-side web applications. Consequently, much of the burden on the backend is reduced, leading to much lighter web applications.

Bootstrapper[edit]

There are three phases of the AngularJS bootstrapper[2] that occur after the DOM completes loading:

  1. Create a new Injector
  2. Compile service - The Compile service is like compiling in C or C++. It walks the DOM and locates all the directives such as "ng-app".
  3. Link phase - The link phase attaches all the directives to scope.

Notable directives[edit]

AngularJS directives allow the developer to specify custom and reusable HTML tags that moderate the behavior of certain elements.

ng-app
Declares an element as a root element of the application allowing behavior to be modified through custom HTML tags.
ng-bind
Changes the text of an element to the value of an expression.<span ng-bind="name"></span> will display the value of ‘name’ inside the span. Any changes to ‘name’ are reflected instantly in the DOM anywhere the variable is used.
ng-model
Similar to ng-bind, but allows two-way data binding between the view and the scope.
ng-class
Allows class attributes to be dynamically loaded.
ng-controller
Specifies a JavaScript controller class that evaluates HTML expressions.
ng-repeat
Instantiate an element once per item from a collection.
ng-show & ng-hide
Conditionally show or hide an element, depending on the value of a boolean expression. Show and hide is achieved by setting the CSS display style.
ng-switch
Conditionally instantiate one template from a set of choices, depending on the value of a selection expression.
ng-view
The base directive responsible for handling routes that resolve JSON before rendering templates driven by specified controllers.
ng-if
Basic if statement directive which allow to show the following element if the conditions are true. When the condition is false, the element is removed from the DOM. When true, a clone of the compiled element is re-inserted

Two-way data binding[edit]

AngularJS' two-way data binding is its most notable feature and reduces the amount of code written by relieving the server backend from templating responsibilities. Instead, templates are rendered in plain HTML according to data contained in a scope defined in the model. The $scope service in Angular detects changes to the model section and modifies HTML expressions in the view via a controller. Likewise, any alterations to the view are reflected in the model. This circumvents the need to actively manipulate the DOM and encourages bootstrapping and rapid prototyping of web applications.[3] AngularJS detects changes in models by comparing the values with stored earlier values in a process of dirty-checking, unlike Ember.js and Backbone.js which trigger listeners when the model values are changed.[4]

Chrome plugin[edit]

In July 2012, the Angular team built a plugin for the Google Chrome browser called Batarang,[5] that improves the debugging experience for web applications built with Angular. The extension aims to allow for easy detection of performance bottlenecks and offers a GUI for debugging applications.[6] The extension is not compatible with recent releases of Angular.

Legacy browser support[edit]

Versions 1.2 and later of AngularJS do not support Internet Explorer versions 6 or 7.[7] Versions 1.3 and later of AngularJS drop support for Internet Explorer 8.[8]

Development history[edit]

AngularJS was originally developed in 2009 by Miško Hevery and Adam Abrons [9] at Brat Tech LLC[10] as the software behind an online JSON storage service, that would have been priced by the megabyte, for easy-to-make applications for the enterprise. This venture was located at the web domain "GetAngular.com",[10] and had a few subscribers, before the two decided to abandon the business idea and release Angular as an open-source library.[citation needed]

Abrons left the project, but Hevery, who works at Google, continues to develop and maintain the library with fellow Google employees Igor Minár and Vojta Jína.[11]

Releases[edit]

Releases 1.0.x and 1.2.x are the stable versions, whereas 1.1.x contained breaking changes between minor releases (i.e. 1.1.x – 1.1.y).[12]

The code names are super-power related, composed of two hyphen-joined words, should sound “fun / crazy / cool”, and are publicly submitted and voted by users.[13]

AngularJS versions
Release Dates Version Codename
Jul 25, 2014 1.2.21 wizard-props (stable)
Jul 25, 2014 1.3.0-beta.17 turing-autocompletion (unstable)
Jul 18, 2014 1.3.0-beta.16 pizza-transubstantiation (unstable)
Jul 11, 2014 1.3.0-beta.15 unbelievable-advancement (unstable)
Jul 11, 2014 1.2.20 accidental-beautification (stable)
Jul 1, 2014 1.3.0-beta.14 harmonious-cacophonies (unstable)
Jul 1, 2014 1.2.19 precognitive-flashbacks (stable)
Jun 16, 2014 1.3.0-beta.13 idiosyncratic-numerification (unstable)
Jun 13, 2014 1.3.0-beta.12 ephemeral-acceleration (unstable)
Jun 13, 2014 1.2.18 ear-extendability (stable)
Jun 6, 2014 1.3.0-beta.11 transclusion-deforestation (unstable)
Jun 6, 2014 1.2.17 quantum disentanglement (stable)
May 23, 2014 1.3.0-beta.10 excessive-clarification (unstable)
May 16, 2014 1.3.0-beta.9 release-naming (unstable)
May 09, 2014 1.3.0-beta.8 accidental-haiku (unstable)
Apr 25, 2014 1.3.0-beta.7 proper-attribution (unstable)
Apr 21, 2014 1.3.0-beta.6 expedient-caffeination (unstable)
Apr 3, 2014 1.3.0-beta.5 chimeric-glitterfication (unstable)
Apr 3, 2014 1.2.16 badger-enumeration (stable)
Mar 28, 2014 1.3.0-beta.4 inconspicuous-deception (unstable)
Mar 21, 2014 1.2.15 beer-underestimating (stable)
Mar 21, 2014 1.3.0-beta.3 emotional-waffles (unstable)
Mar 14, 2014 1.3.0-beta.2 silent-ventriloquism (unstable)
Mar 8, 2014 1.3.0-beta.1 retractable-eyebrow (unstable)
Mar 1, 2014 1.2.14 feisty-cryokinesis (stable)
Feb 14, 2014 1.2.13 romantic-transclusion (stable)
Feb 7, 2014 1.2.12 cauliflower-eradication (stable)
Feb 3, 2014 1.2.11 cryptocurrency-hyperdeflation (stable)
Jan 24, 2014 1.2.10 augmented-serendipity (stable)
Jan 15, 2014 1.2.9 enchanted-articulacy (stable)
Jan 10, 2014 1.2.8 interdimensional-cartography (stable)
Jan 3, 2014 1.2.7 emoji-clairvoyance (stable)
Dec 19, 2013 1.2.6 taco-salsafication (stable)
Dec 13, 2013 1.2.5 singularity-expansion (stable)
Dec 6, 2013 1.2.4 wormhole-blaster (stable)
Nov 27, 2013 1.2.3 unicorn-zapper (stable)
Nov 22, 2013 1.2.2 consciousness-inertia (stable)
Nov 14, 2013 1.2.1 underscore-empathy (stable)
Nov 8, 2013 1.2.0 timely-delivery (stable)
Oct 15, 2013 1.2.0rc3 ferocious-twitch (unstable)
Sep 4, 2013 1.2.0rc2 barehand-atomsplitting (unstable)
Aug 22, 2013 1.0.8 bubble-burst (stable)
Aug 13, 2013 1.2.0rc1 spooky-giraffe (unstable)
May 22, 2013 1.0.7 monochromatic-rainbow (stable)
May 22, 2013 1.1.5 triangle-squarification (unstable)
Apr 4, 2013 1.0.6 universal-irreversibility (stable)
Apr 3, 2013 1.1.4 quantum-manipulation (unstable)
Feb 22, 2013 1.1.3 radioactive-gargle
Feb 20, 2013 1.0.5 flatulent-propulsion
Jan 22, 2013 1.1.2 tofu-animation
Jan 22, 2013 1.0.4 bewildering-hair
Nov 26, 2012 1.1.1 pathological-kerning
Nov 26, 2012 1.0.3 bouncy-thunder
Aug 31, 2012 1.1.0 increase-gravatas
Aug 31, 2012 1.0.2 debilitating-awesomeness
Jun 25, 2012 1.0.1 thorium-shielding
Jun 13, 2012 1.0.0 temporal-domination (stable)[12]
Jun 12, 2012 1.0.0rc12 regression-extermination
Jun 10, 2012 1.0.0rc11 promise-resolution
May 23, 2012 1.0.0rc10 tesseract-giftwrapping
May 14, 2012 1.0.0rc9 eggplant-teleportation
May 6, 2012 1.0.0rc8 blooming-touch
Apr 30, 2012 1.0.0rc7 rc-generation
Apr 20, 2012 1.0.0rc6 runny-nose
Apr 12, 2012 1.0.0rc5 reality-distortion
Apr 5, 2012 1.0.0rc4 insomnia-induction
Mar 29, 2012 1.0.0rc3 barefoot-telepathy
Mar 20, 2012 1.0.0rc2 silence-absorption
Mar 13, 2012 1.0.0rc1 moiré-vision
Jan 17, 2012 0.10.6 bubblewrap-cape
Nov 8, 2011 0.10.5 steel-fist
Oct 22, 2011 0.10.4 human-torch
Oct 13, 2011 0.10.3 shattering-heartbeat
Oct 8, 2011 0.10.2 sneaky-seagull
Sep 9, 2011 0.10.1 inexorable-juggernaut
Sep 2, 2011 0.10.0 chicken-hands
Aug 20, 2011 0.9.19 canine-psychokinesis
Jul 29, 2011 0.9.18 jiggling-armfat
Jun 30, 2011 0.9.17 vegetable-reanimation
Jun 7, 2011 0.9.16 weather-control
April 11, 2011 0.9.15 lethal-stutter
April 1, 2011 0.9.14 key-maker
Mar 13, 2011 0.9.13 curdling-stare
Mar 3, 2011 0.9.12 thought-implanter
Feb 8, 2011 0.9.11 snow-maker
Jan 26, 2011 0.9.10 flea-whisperer
Jan 13, 2011 0.9.9 time-shift
Dec 23, 2010 0.9.8 astral-projection
Dec 10, 2010 0.9.7 sonic-scream
Dec 6, 2010 0.9.6 night-vision
Nov 25, 2010 0.9.5 turkey-blast
Nov 18, 2010 0.9.4 total-recall
Nov 10, 2010 0.9.3 cold-resistance
Nov 3, 2010 0.9.2 faunal-mimicry
Oct 26, 2010 0.9.1 repulsion-field
Oct 20, 2010 0.9.0 dragon-breath

Comparisons to Backbone.js[edit]

Data-binding
The most prominent feature that separates the two libraries is in the way models and views are synchronized. Whereas AngularJS supports two way data-binding, Backbone.js relies heavily on boilerplate code to harmonize its models and views.[14]
REST
Backbone.js communicates well with RESTful backends. A very simple use of REST APIs is also available with AngularJS using the $resource service. AngularJS also provides a $http service which is more flexible, connecting to remote servers either through a browser's XMLHttpRequest object or via JSONP.[15]
Templating
AngularJS templating uses a combination of customizable HTML tags and expressions. Backbone.js ships with underscore.js's utility function template() and also integrates with different templating engines such as Mustache.[14]

See also[edit]

References[edit]

Further reading[edit]

External links[edit]