A Developer’s Guide to Start Learning AngularJS

angularjs

Each individual living in this era is dwelled into such environment where he invests most of his day dealing with web. Each business is also looking forward to making a strong web presence over the internet to grab maximum reach. In short, the entire focus is on gaining the business via improving your online presence.

Adopting a robust platform to make feature-rich web applications is the beneficial approach in the above scenario. The dynamic web applications have taken a big space in today’s advanced era which leads to the popularity of JavaScript and AngularJS front-end framework.

What is AngularJS?

AngularJS is a feature-rich open-source web application built by Google. Its major aim is to enable easy testing and rich front-end development. With fewer codes, AngularJS web development is simple to start.

Technically, it is a structural framework to create dynamic web apps where HTML can be used as the template language. It enables to extend the capabilities of HTML syntax and allows clearer explanation of the components of your application.

Precisely, it can be seen as adding few attributes to your HTML and you have with you a basic Angular app in your hands. But practically implementing any language is not a piece of cake. It involves rigorous knowledge and practical implementation of those concepts to understand them well.

A smart approach here is to learn the basic and each minor concept of this front-end framework and gain expertise in its practical use, but before this you have to thoroughly understand what are the advantages you get from this web framework.

The below listed AngularJS features and basic fundamentals can help you get better understanding of this web development framework and enables you to build web applications with host of features injected into it.

Two-Way Data Binding

It is considered to be the most powerful feature of AngularJS that minimizes the effort of developers to write code and allows less server back-end burden. In general, a big portion of the code base of a web application comprises traversing and manipulating the DOM. Here, data-binding lets this code be treated as invisible, thus allowing you to have a keen eye on other crucial aspects of the application.

 

The traditional development process follows one-way data binding where the template and model components are merged in the form of a view. But after this merging, changes do not appear automatically in the view, and thus DOM elements and attributes are required to be manipulated manually to reflect those changes.

The above process becomes more complex while updating a view. Instead, the two-way data binding in AngularJS causes a smooth synchronization of data between DOM and model.

Templates

A template is written in AngularJS with HTML comprising Angular-specific attributes and elements. Here, AngularJS renders the dynamic view in browsers via adjoining the template with information from the controller and model.

The Angular elements and attributes that can be used are below:

Filter: meant for formatting of data to be showcased

Form Controls: a good mode for user input validation.

Markup: use double curly brace notation {{ }}, to bind expressions to elements.

Directive: allows rendering a reusable DOM component or elongating an existing DOM element.

You can set up the template like below-

<html ng-app>

<!-- Body tag augmented with ngController directive  -->

<body ng-controller="MyController">

  <input ng-model="foo" value="bar">

  <!-- Button tag with ngClick directive, and

         string expression 'buttonText'

         wrapped in "{{ }}" markup -->

  <button ng-click="changeFoo()">{{buttonText}}</button>

  <script src="angular.js">

</body>

</html>

Directives

It is the most unique and powerful feature available with AngularJS that allows to build reusable and custom HTML components. It is basically considered as the markers on a DOM element like attribute, comment or element name. This notifies the HTML compiler to affix a specific behavior to the concerned element of DOM.  

Directives have the primary usage to disguise complex DOM structure along with decorating few elements with behavior. Through its optimum usage, you can extend your HTML as it lets you create new HTML syntax. AngularJS is made to incorporate its functionality into the page. Started with ng-, entire Directives in list occur in HTML attributes and thus act as the standalone elements.

The 3 basic directives primarily used with the AngularJS are as follows:

ng-app

It is a plumbing directive and AngularJS keeps an eye to choose that HTML element which has this directive being attached with it. It is further used with the Bootstrap application. The added advantage of using it is that it can be put on any element of HTML and a module can be connected to it.

ng-controller

Another plumbing directive that connects a model with the related behaviors to a HTML tree branch, that can be made available for the use of ng-app.

ng-bind

A plumbing directive meant to connect a model behavior result to the HTML element text content.

Modules

Every aspect of Angular is available inside a module. It can be treated as a container for diverse parts of your app, including filters, directives, controllers and similar one. Every module has a unique name within the application of use. Modules can be used within other modules for added functionality.

The empty array is used for declaring those modules that an app will be using. They are treated as dependencies, as your app is dependent on them to run.

The one basic thing about modules is that they are used to put a hold onto our controllers and related similar code about our application. It also prevents code declaration at a global scope as it is available within the module.

The modules results in easier declarative process, and they basically aim to specify the process of how a Bootstrap can be matched with an application. Code can be used as the reusable modules and the unit tests need to use load only the relevant modules to keep them fast.

Controllers

It is a JavaScript constructor function which is attached to the DOM through the directive ng-controller. Now, a child scope has been built which is available live like a parameter. A controller can be used to add behavior and set up the initial state of the scope object. However, it cannot be used for DOM manipulation and state share.

For these purposes, data-binding, directives and Angular services are made specifically to produce better performance.

Scopes

Scope is simply an object which refers to the application model and provides APIs to notice model mutations and also to propagate any model changes. They are arranged in hierarchical format to imitate the DOM structure. A scope is like an adhesive bond between the view and application controller.

You can set up the scope in the following way:

var app = angular.module('Todo', []);

app.controller('TodoCtrl', function($scope) {

});

The directives set the watch expressions during template linking which allows the directives to be intimated about property changes and to render the modified value to DOM. Here, there exists a slight wall to prevent communication of directive and DOM from the controller, although controllers and directives are kept as separate entities here. It greatly improves the testing area of the applications since controller’s view is made agnostic here.

Testing

Like any other application, testing is the crucial phase while creating AngularJS applications. As it does not make the use of a compiler, the JavaSvript code needs to go through a series of finer tests to remove any kind of flaws if persist.

AngularJS has an end to end test runner called protractor that genuinely understands its inner workings and works authentically to eliminate the test flakiness. User interaction simulation is also noticed in the above process.

Benefits of AngularJS

There are numerous advantages which this web development framework offers you when you implement it in your web apps.

  • MVC, Model View Controller pattern has been used to optimally manage the web applications.
  • HTML can be extended by affixing directives to the markup having new attributes and expressions. It allows the usage of powerful templates.
  • Creating own directives and crafting reusable components is a plus point.
  • It follows two-way data binding where your HTML views are connected with the JavaScript objects. With this, you don’t need DOM manipulation and your model will be immediately reflected into your view.
  • Structuring and testing JavaScript code is so easy.
  • There are plenty of services offered by AngularJS that can be injected into the controllers to utilize utility code.
  • It makes use of plain old JavaScript objects.
  • Its markup lives in the DOM and leverages dependency injection.

The above factors are quite beneficial in making web apps and add weightage to this efficient technology, unlike the same in leak, like ReactJS.

Conclusion

AngularJS with its awesome features is becoming the favorite choice of most of the web application developers. There is so much beyond the extensive functions which this front-end framework offers to the diversified businesses with unique requirements.

The above blog is written with the motto to make readers aware of the basic concepts of AngularJS so that they can do app development with expanded benefits. All the integral parameters and features are included in the list and neatly described to put transparency in each minor concept. You can explore and make the best use of them to make full-fledged web applications.

About The Author: dmeyer

David Meyer is an experienced JavaScript developer working with CSSChopper from few years. With a sound expertise in AngularJS web applications, he loves to write informative blogs to spread awareness no this efficient JavaScript framework.

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