Angular JS

Angular JS – a framework for dynamic web applications from Google.

Angular JS was created for developers who believe that a declarative style is better for creating a UI, and an imperative one is for writing business logic.

Angular JS tasks
Examples
Angular JS Concepts
- Directives
- Scopes
- Services
- Modules
- Testing

Here you can hire remote developers who are working on Angular technology — Development on AngularJS

Angular JS tasks

To separate the DOM manipulation from the application logic. This greatly improves code testability.

Automated application testing is good and important as writing the application itself. The testability depends on how the code is structured.

To separate the development of the client from the server. This allows parallel development and improves reuse on both sides.

The framework guides the developer throughout the entire development cycle of the application: from designing the UI through writing business logic to test.

Common tasks become trivial, and complex ones become simpler.

Hire Angular JS developer

Angular JS is a comprehensive framework. The standard package provides the following features:

All you need to create CRUD applications: data-binding, basic template directives, form validation, routing, deep linking, component reuse, dependency injection, tools for interacting with server (RESTful) data sources.

All you need for testing: tools for unit testing, end-to-end testing, mock.

A sample application template that includes a directory structure and test scripts.

Angular JS is developed by Google and used in at least one Google service – DoubleClick.

Examples:

Simple todo:

AngularJS Concepts

Directives

Almost the entire declarative part of AngularJS is based on directives. They are used to enrich the HTML syntax. During the compilation of the DOM, directives are taken from HTML and executed.

Directives may add some new behavior and/or modify the DOM. The standard package includes a fairly large number of directives for building web applications. But a key feature is the ability to develop their own directives, whereby HTML can be turned into DSL.

Directives are named using lowerCamelCase, for example, ngBind. When using, the directive must be named in lower case using one of the special characters as a separator::, -, or _.

Optionally, you can use x- or data- prefixes to get valid code. Examples: ng: bind, ng-bind, ng_bind, x-ng-bind and data-ng-bind.

Directives can be used as an element ( ), an attribute (), in a class (), or in a comment (). It depends on how a particular directive was developed.

Scopes

A scope is an object related to the model in the application. It is the execution context for expressions. Scopes are arranged in a hierarchical structure similar to the DOM. At the same time, they inherit properties from their parent scope.

Scopes are like glue between the controller and the view. In the process of executing the template binding phase, the directives set the watch ($ watch) for expressions within the scope. $ watch gives directives the ability to respond to changes to display an updated value or some other action.

Both controllers and directives have a reference to scope but do not have references to each other.

So controllers are isolated from directives and from the DOM. Due to this, the possibilities for testing the application increase.

Services

Services are singletons that perform a specific task that is common to all or to a specific web application. For example, the $http service, which is a wrapper over XMLHttpRequest. A few examples of other services:

$compile – a compilation of the HTML string or part of the DOM into a template linking the template to a specific scope;

$cookies – provides read/write access to cookies.

$location – work with the address bar

$resource – a factory for creating resource objects intended for interaction with server (RESTful) data sources;

To use a service you must specify it as a dependency for the controller, another service, directive, etc. AngularJS takes care of the rest – creating, resolving dependencies, etc.

Filters are designed to format data before displaying it to the user, as well as filtering items in collections. Examples of filters (a full list can be found in the documentation): currency, date, orderBy, uppercase. Using filters is pretty traditional: {{expression | filter1 | filter2}}

Modules

Applications in Angular JS do not have a primary executable method. Instead, the module serves as a declarative description of how the application should be downloaded.

Due to this, for example, when writing test scripts, you can load additional modules that will override some settings, thereby facilitating complex (end-to-end) testing.