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Introduction Angularjs


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Introduction Angularjs

Hi everyone in this blog I’m explaining about angularjs.

What is Angularjs?

AngularJS is a structural framework for dynamic web apps. It lets you use HTML as your template language and lets you extend HTML's syntax to express your application's components clearly and succinctly. Angular's data binding and dependency injection eliminate much of the code you would otherwise have to write. And it all happens within the browser, making it an ideal partner with any server technology.

Angular is what HTML would have been had it been designed for applications. HTML is a great declarative language for static documents. It does not contain much in the way of creating applications, and as a result building web applications

The impedance mismatch between dynamic applications and static documents is often solved with:

  1. A library - a collection of functions which are useful when writing web apps. Your code is in charge and it calls into the library when it sees fit. E.g., Jquery.
  2. Frameworks - a particular implementation of a web application, where your code fills in the details. The framework is in charge and it calls into your code when it needs something app specific. E.g., durandal, ember, etc.

Angular takes another approach. It attempts to minimize the impedance mismatch between document centric HTML and what an application needs by creating new HTML constructs. Angular teaches the browser new syntax through a construct we call directives. Examples include:

Client side solution:

Angular is not a single piece in the overall puzzle of building the client-side of a web application. It handles all of the DOM and AJAX glue code you once wrote by hand and puts it in a well-defined structure. This makes Angular opinionated about how a CRUD application should be built. But while it is opinionated, it also tries to make sure that its opinion is just a starting point you can easily change. Angular comes with the following out-of-the-box:

1.       Everything you need to build a CRUD app in a cohesive set: data-binding, basic templating directives, form validation, routing, deep-linking, reusable components, dependency injection.

2.       Testability story: unit-testing, end-to-end testing, mocks, test harnesses.

3.       Seed application with directory layout and test scripts as a starting point.

Angular simplifies application development by presenting a higher level of abstraction to the developer. Like any abstraction, it comes at a cost of flexibility. In other words not every app is a good fit for Angular. Angular was built with the CRUD application in mind. Luckily CRUD applications represent the majority of web applications. To understand what Angular is good at, though, it helps to understand when an app is not a good fit for Angular.

 

1.       Template: HTML with additional markup

2.       Directives: extend HTML with custom attributes and elements

3.       Model: the data shown to the user in the view and with which the user interacts

4.       Scope: context where the model is stored so that controllers, directives and expressions can access it

5.       Expressions: access variables and functions from the scope

6.       Compiler: parses the template and instantiates directives and expressions

7.       Filter: formats the value of an expression for display to the user

8.       View: what the user sees (the DOM)

9.       Data Binding: sync data between the model and the view

10.   Controller: the business logic behind views

11.   Dependency Injection: Creates and wires objects and functions

12.   Injector: dependency injection container

13.   Module: a container for the different parts of an app including controllers, services, filters, directives which configures the Injector

14.   Service: reusable business logic independent of views

DataBinding:

In the following example we will build a form to calculate the costs of an invoice in different currencies.

Let's start with input fields for quantity and cost whose values are multiplied to produce the total of the invoice:

<link href="~/Content/bootstrap/css/bootstrap.min.css" rel="stylesheet" />

<script src="~/Scripts/angular.min.js"></script>

<div class="clearfix">&nbsp;</div>

<div class="clearfix">&nbsp;</div>

<div class="container">

    <div class="row">

        <div class="col-md-6 col-md-offset-3 well">

            <h2 class="text-center text-primary">Invoice</h2>

            <hr />

            <div class="table-responsive">

                <table class="table table-bordered table-striped" ng-app>

                    <tr>

                        <td>Total Product:</td>

                        <td>

                            <input type="number" min="0" ng-model="qty"></td>

                    </tr>

                    <tr>

                        <td>Price:</td>

                        <td>

                            <input type="number" min="0" ng-model="cost"></td>

                    </tr>

                    <tr>

                        <td>Total Price</td>

                        <td>{{qty * cost | currency}}</td>

                    </tr>

                </table>

            </div>

        </div>

    </div>

</div>

 

 

Output:

in my next post i'll explain about Jquery Validation Client side


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