What is AngularJS

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies. You can also create your own AngularJS directives to implement any necessary Software Developer Hourly Rate custom functionality you need in a web application. In fact, you should use your own custom directives to do any direct DOM manipulation that a web application needs. If you recall, this is the equivalent of using ng-bind in AngularJS. In Angular you’re required to use parentheses inside of brackets (known as “banana in a box”) for two way data binding.

understanding angularjs

However, we did not address how directives manipulate data objects that are defined in the Angular app. In certain use cases, the directive might need to use the objects and functions defined in the controller—manipulate their values and make calls to the functions. In this post we shall explore how this is done from within a directive. In Angular 1.0.2 or earlier, typing into the textboxes changes the values in the gray boxes, which are only visible in the child scopes. (See Artem’s explanation as to why on StackOverflow.) What we want is for the inputs to affect the myArrayOfPrimitives array, not a child scope primitive property.

Factory() is a method that takes a name and function that are injected in the same way as in service. The major difference between an AngularJS service and an AngularJS factory is that a service is a constructor function NET Framework Wikipedia and a factory is not. That is why, in the case of a factory, we return an object literal instead of using this. It’s important to note that Controllers, Services and Directives all have their own nested scopes.


As libraries and frameworks are introduced to the community, developers with a distinct need for that functionality will use and test the new solutions. After feedback cycles and several versions, the most viable solutions will rise to the top, be featured at conferences and on blogs, and become well known as trusted tools. The aforementioned jQuery, created by John Resig, is a great example of this. It started out as a lightweight library to simplify the modification of the DOM, which is the representation of the HTML structure of a Web page. For all scopes , Angular always tracks a parent-child relationship (i.e., a hierarchy), via scope properties $parent, $$childHead and $$childTail. The prototype chain is not consulted, and a new aString property is added to the childScope.

When we call service() function, factory() is the one that is actually called by passing a function that instantiates an object by the constructor. In simple words, we can say that service calls a predefined factory. HTML, of course, provides the semantic markup of the content on a page. HTML 5 offers several new tags primarily focused on the semantic structure of a document including Article, Section and Footer, just to name a few.

understanding angularjs

The value of the scope field defines how the scope of the directive will be created and used. One of the best features of AngularJS is the built-in data binding. Data binding is the process of linking data from the model with what is displayed in a web page. AngularJS provides a very clean interface to link the model data to elements in a web page. Each view or web page in AngularJS has a single module assigned to it via the ng-app directive. (Directives are discussed later in this chapter.) However, you can add other modules to the main module as dependencies, which provides a very structured and componentized application.


Implementing functionality in AngularJS becomes more modular and reusable if the code has directives defined. And the application of directives becomes more maintainable and robust if the directive scope is well constructed. Top 15 Data Analysis Tools For Managing Data Like A Pro Dependency injection is a process in which a code component defines dependencies on other components. When the code is initialized, the dependent component is made available for access within the component.

  • The major difference between an AngularJS service and an AngularJS factory is that a service is a constructor function and a factory is not.
  • This makes it easier to package and reuse parts of an application.
  • Templates can be defined in several ways, but it’s common to define each in its own HTML file deployed with the application.
  • AngularJS is a JavaScript framework that is used to create dynamic web applications.
  • As I’m sure you know if you are reading this, the AngularJS team is planning for a major version release “very soon” that will include some major paradigm shifts.

But despite being very powerful, you shouldn’t use expressions to implement any higher-level logic. Since I happen to be a huge fan of motor racing and Formula 1, I’ll use an autosport API service to act as our back-end. Luckily, the guys at Ergast are kind enough to provide a free motorsport API that will be perfect for us.

Adding Controllers

With that, you can move your model and business logic to the front-end and build back-end agnostic web apps. The data binding model in AngularJS is both simple and powerful. The majority of the binding model involves declarative statements in the HTML templates which enables AngularJS to keep the DOM elements and JavaScript objects synchronized.

The factory is a function in AngularJS that is used to return the values whenever the controller needs it. Once the value is created it can be reused by all the services and controllers. In AngularJS, this was true for things like services (e.g. \$http), but now we have to import basic directives like NgModel first . This may seem like a frustrating change, but it ultimately allows you to explicitly control the overhead of your Angular applications which is a good thing. Closely related to templates is the notion of binding data, in the form of JavaScript objects, to the HTML elements on the page.

In this case, the avatar will only show up once the driver object has been loaded into the scope by the controller. The ng-controller directive defines which controller will be in charge of your view. In this case, we denote the driversController, which will provide our list of drivers . It includes a mocking module and support for mocking things like the HTTP service in your unit tests.

Note that the displayfunction bound in the directive is defined in the controller scope. Let’s continue with the example of the movie directive and add more properties to the scope method so as to understand all of these prefixes. In this case, the movie title in both the header section and the directive is initialized to the same value defined in the controller’s scope, Ice Age.

Factory Vs Service

In this article, we will discuss AngularJS, one of the best frameworks, and what is the usage of service function and factory function in AngularJS. Controllers are just Javascript objects that create scope , setting up attributes and functions. It’s the connection point for all scopes, functions and data sources in the application. These are similar to traffic cops that direct the flow and send data back and forth between the parts of your application. AngularJS extends HTML by providing directives that add functionality to your markup and allow you to create powerful dynamic templates.

Custom HTML elements used to enable and interact with AngularJS. This cool feature is how we instantiate your app (`ng-app`) or create custom elements that transform data and views with JS logic stored in your models and controllers. It also implements two-way data binding, connecting your HTML to your JavaScript objects seamlessly. In simple terms, this means that any update on your model will be immediately reflected in your view without the need for any DOM manipulation or event handling (e.g., with jQuery).


Components combine concepts that we are already familiar with from AngularJS. The Angular 2 Component combines the AngularJS Directive, Controller, and Scope. My article will attempt to make you more comfortable with components by comparing them to what you already know from AngularJS.

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