Welcome!

@ThingsExpo Authors: Liz McMillan, Elizabeth White, Yeshim Deniz, Pat Romanski, William Schmarzo

Related Topics: @ThingsExpo, Java IoT, Mobile IoT, Microservices Expo, Linux Containers, Containers Expo Blog, Machine Learning , Agile Computing, Video, Wearables, @CloudExpo, FinTech Journal, @DevOpsSummit

@ThingsExpo: Blog Feed Post

Angular 2 Overview By @YFain | @ThingsExpo #DevOps #IoT #Microservices

The Angular 2 framework is a re-write of popular framework AngularJS

This article was excerpted from the book “Angular Development With TypeScript” (see http://bit.ly/1QYeqL0).

The Angular 2 framework is a re-write of popular framework AngularJS. In short, the newer version has the following advantages over AngularJS.

  • The code is simpler to write and read
  • It performs better  than AngularJS
  • It’s easier to learn
  • The application architecture is simplified as it’s component-based

This article contains a high-level overview of Angular highlighting improvements comparing to AngularJS. For a more detailed architecture overview of Angular visit product documentation at http://bit.ly/1TQJmwG.

Code Simplification
First of all, an Angular application consists of standard ES6 modules. Typically one module is one file. There is no need to use a framework-specific syntax for loading and using modules. Just use the universal module loader SystemJS (covered in Chapter 2) and add import statements to use functionality implemented in the loaded modules. You don’t need to worry about the proper order of the <script> tags in your HTML files. If a module A needs the functionality from a module B, just import the module B inside module A.

The HTML file of the landing page of your application just includes the framework modules, and your application code is bootstrapped by simple loading of the root component of your application. All child modules will be loaded automatically based on the import statements. Below is a typical content of the index.html of an Angular application. In the top portion you include the required framework modules, and at the bottom you configure the system loader and load the root component located in the file app/my_application.ts. The <app> tag is a selector defined in that root component.

<!DOCTYPE html>
<html>
<head>
<script src="node_modules/angular2/bundles/angular2-polyfills.js"></script>
<script src="node_modules/typescript/lib/typescript.js"></script>
<script src="node_modules/systemjs/dist/system.src.js"></script>
<script src="node_modules/rxjs/bundles/Rx.js"></script>
<script src="node_modules/angular2/bundles/angular2.dev.js"></script>

</head>
<body>
<app>Loading...</app>

<script>
System.config({
transpiler: 'typescript',
typescriptOptions: {emitDecoratorMetadata: true},
packages: {app: {defaultExtension: 'ts'}}
});
System.import('app/my_application');
</script>
</body>
</html>

The HTML fragment of each application component is either inlined inside of the component (the template property) or in the file referenced from the component using the property templateURL. The latter option allows designers to work on the UI of your application without the need to learn Angular.

An Angular component is a centerpiece of the new architecture. The next Figure shows a high-level diagram of a sample Angular application.

ch1_angular2_workflow

The simplest way of declaring a component is writing a class in TypeScript (you can use ES5, ES6, or Dart as well). Let’s do an experiment. We’ll give you a super brief intro on how to write Angular components in TypeScript followed by the sample code. See if you can understand the code with minimum explanations.

An annotated TypeScript class represents a component. The annotation @Component contains the property template that declares an HTML fragment to be rendered by the browser. The HTML piece may include the data binding expressions, which can be represented by double curly braces. If a view depends on other components, the @Component annotation has to list them in the property directives. The references to the event handlers are placed in the markup from the @Component section and are implemented as methods of the class.

The annotation @Component also contains a selector declaring the name of the custom tag to be used in HTML document. When Angular sees an HTML element with the name matching a selector, it knows which component implements it. The HTML fragment below illustrates a parent component with one child component :

<body>
<auction-application>
<search-product [productID]= "123"></search-product>
</auction-application>
</body>

A parent component sends the data to its child components using property binding (note the square brackets above), and children communicate with their parents by sending events. Figure 1.7 shows the main page (the parent component) with its child components surrounded with thick borders.

Below is a code sample of a SearchComponent, and we can include it in an HTML document as because its declaration includes the selector property with the same name.

@Component({
selector: 'search-product',
template:

` <form>
<div>
<input id="prodToFind" #prod>
<button (click)="findProduct(prod.value)">Find Product</button>
Product name: {{product.name}}</div>
</form>


` })
class SearchComponent {
@Input() productID: number;

product: Product; // code of the Product class is omitted

findProduct(prodName: string){
// Implementation of the click handler goes here
}
// Other code can go here
}

If you are familiar with any object-oriented language that has classes you should understand most of the above code. The annotated class SearchComponent declares a variable product, which may represent an object with multiple properties, one of which (name) is bound to the view ({{product.name}}). The #prod will have a reference to the hosting <input type=”text” /> element so you don’t need to query DOM to get the entered value.

The (click) notation represents a click event, and the event handler function gets the argument value from the input parameter productID that will be populated by the parent component via binding.

This was just a quick look at the sample component, but we’ll be providing a detailed description of what components are made up of starting from the next chapter.

If you never worked with classes before, no worries. We’ll cover them in Appendices A and B. The next Figure illustrates the inner working of a component.

ch1_angular_component

A component uses the data from a model (the M in the MVC pattern), which can be also represented by a class. In TypeScript the model class for a SearchComponent could look like this:

class Product{
id: number,
name: string;
description: string;
bid: number;
price: number;

// constructor and other methods go here
}

Note that TypeScript allows you to declare class variables with types. To let the UI component SearchComponent know about its model you can refer to it by declaring a class variable, e.g., product:

@Component { // code omitted for brevity}
class SearchComponent {
product: Product; // the model

findProduct(productID){
// The implementation of the click handler
// for the Find Components button goes here
}
}

If the search component may return multiple products we can declare an array to store them:

products: Array<Product>;

The generics notation (explained in Appendix B) tells the TypeScript compiler that only the objects of the type Product are allowed to be stored in this array.

In Angular there are no separate controllers (the C in the MVC pattern). The component includes all required code. In our example, the SearchProduct class would contain the code performing the controller’s responsibilities in addition to being a UI component on the HTML view. For a cleaner separation of TypeScript and HTML, the content of the template section of the @Component annotation can be stored in a separate file by using templateURL instead of template, but it’s a matter of your preference.

Developers who know AngularJS can think of a component as a directive with a view, but writing directives without views is still allowed.

Now let’s see how the design of Angular is simpler than of AngularJS. In AngularJS all directives were loaded to the global memory, whereas in Angular you specify the required directives on the component level providing better encapsulation.

You don’t have to deal with the hierarchy of scope objects as in AngularJS. Angular is component based, and the properties are created on the this object, which becomes the component’s scope.

Dependency Injection is a design pattern that inverts the way of creating objects your code depends on. Instead of explicitly creating object instances (e.g. with new) the framework will create and inject them into your code. Angular comes with a dependency injection module. We’ll cover dependency injection in Chapter 4.

In AngularJS there were several ways of injecting dependencies, which could be confusing at times. In Angular you can inject dependencies into the component only via its constructor. The following TypeScript code fragment shows how to inject the ProductService component into the SearchComponent. You just need to specify a provider and declare the constructor argument with the type that matches provider’s type.

@Component({
selector: 'search-product',
viewProvider: [ProductService],
template:[
<div>
...
<div>]
})
class SearchComponent {
products: Array<Product> = [];

constructor(productService: ProductService) {
this.products = this.productService.getProducts();
}
}

To summarize, Angular is simpler than AngularJS because of the following:

  • Each building block of your app is a component with well encapsulated functionality of a view, controller, and auto-generated change detector.
  • Components can be programmed as annotated classes.
  • A developer doesn’t have to deal with scope hierarchies.
  • Dependent components are injected via the component’s constructor.
  • Two-way binding is turned off by default.
  • Change detection mechanism was re-written and works faster.

The concepts of Angular are easy to understand for Java, C#, and C++ programmers, which represent the majority of enterprise software developers. Like it or not, but a framework becomes popular when it gets adopted by enterprises. Today AngularJS is widely adopted by the enterprises, and AngularJS skills are in big demand. Since developing applications with Angular is easier than with AngularJS this trend should continue.

Performance Improvements
To compare performance of AngularJS and Angular 2 the creators of these frameworks developed a benchmarking tool called Benchpress (see http://bit.ly/1IvgnKZ), which showed some serious performance improvements in the area of rendering and memory use.

The rendering improvements are mainly the result of the internal redesign of the Angular framework. The UI rendering and the application API were separated into two layers, which allows to run the non-UI related code in a separate Web Worker thread. Beside the ability to run the code of these layers concurrently, Web browsers allocate different CPU cores to these threads when available. You can find a detailed description of the new rendering architecture in the document titled Angular 2 Rendering Architecture available at http://bit.ly/1CEXjIl.

Creating a separate layer for rendering has an additional important benefit: an ability to use different renderers for different devices. Every component includes the @Component annotation that contains an HTML template defining the look of the component. If you want to create a component to display stock prices in the Web browser its UI portion may look as follows:

@Component({
selector: 'stock-price',
renderer: 'DOMRenderer',
template: '
<div>The price of an IBM share is $165.50</div>
'
})
class StockPriceComponent {
...
}

Currently, DOMRenderer is the only renderer, so you don’t even need to include it in the @Component annotation. But the Angular team already works on creating native renderers for mobile devices running iOS and Android. Such renderers should be released in the near future, and Angular applications won’t need to run inside the Web View (embedded Web browser) on mobile devices – they’ll use native UI components.

A new and improved change detection mechanism is yet another contributor to better performance. Angular doesn’t use two-way binding unless you manually program it. One-way binding simplifies the detection of the changes in an application that may have lots of interdependent bindings. Now if a component has only internal immutable objects, you can mark it as such so it won’t be checked when a change is detected in another component.

Although Angular 2 is a complete re-design of Angular 1, those of you who use AngularJS can start writing code in Angular 2 style by using ng-forward (see http://bit.ly/1PNXFmH). The other approach is to start gradually switching to a newer version of this framework by running Angular 2 and Angular 1 in the same application (see http://bit.ly/1YixNzE), but this would increase the size of the application.

“To learn more about Angular see the book “Angular Development with TypeScript” at http://bit.ly/1QYeqL0 and save 39% with discount code faindz.  For the up to date information about our Angular 2 training visit this page.

More Stories By Yakov Fain

Yakov Fain is a Java Champion and a co-founder of the IT consultancy Farata Systems and the product company SuranceBay. He wrote a thousand blogs (http://yakovfain.com) and several books about software development. Yakov authored and co-authored such books as "Angular 2 Development with TypeScript", "Java 24-Hour Trainer", and "Enterprise Web Development". His Twitter tag is @yfain

@ThingsExpo Stories
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
SYS-CON Events announced today that EARP Integration will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. EARP Integration is a passionate software house. Since its inception in 2009 the company successfully delivers smart solutions for cities and factories that start their digital transformation. EARP provides bespoke solutions like, for example, advanced enterprise portals, business intelligence systems an...
SYS-CON Events announced today that Outscale, a global pure play Infrastructure as a Service provider and strategic partner of Dassault Systèmes, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Founded in 2010, Outscale simplifies infrastructure complexities and boosts the business agility of its customers. Outscale delivers a secure, reliable and industrial strength solution for its customers, which in...
SYS-CON Events announced today that Progress, a global leader in application development, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Enterprises today are rapidly adopting the cloud, while continuing to retain business-critical/sensitive data inside the firewall. This is creating two separate data silos – one inside the firewall and the other outside the firewall. Cloud ISVs oft...
As cloud adoption continues to transform business, today's global enterprises are challenged with managing a growing amount of information living outside of the data center. The rapid adoption of IoT and increasingly mobile workforce are exacerbating the problem. Ensuring secure data sharing and efficient backup poses capacity and bandwidth considerations as well as policy and regulatory compliance issues.
The 21st International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Machine Learning and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding busin...
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 21st International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. @ThingsExpo Silicon Valley Call for Papers is now open.
SYS-CON Events announced today that Interoute has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Interoute is the owner operator of Europe's largest network and a global cloud services platform, which encompasses over 70,000 km of lit fiber, 15 data centers, 17 virtual data centers and 33 colocation centers, with connections to 195 additional partner data centers. Our full-service Unifie...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.
Existing Big Data solutions are mainly focused on the discovery and analysis of data. The solutions are scalable and highly available but tedious when swapping in and swapping out occurs in disarray and thrashing takes place. The resolution for thrashing through machine learning algorithms and support nomenclature is through simple techniques. Organizations that have been collecting large customer data are increasingly seeing the need to use the data for swapping in and out and thrashing occurs ...
SYS-CON Events announced today that Progress, a global leader in application development, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Enterprises today are rapidly adopting the cloud, while continuing to retain business-critical/sensitive data inside the firewall. This is creating two separate data silos – one inside the firewall and the other outside the firewall. Cloud ISVs ofte...
SYS-CON Events announced today that DivvyCloud will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. DivvyCloud software enables organizations to achieve their cloud computing goals by simplifying and automating security, compliance and cost optimization of public and private cloud infrastructure. Using DivvyCloud, customers can leverage programmatic Bots to identify and remediate common cloud problems in rea...
Amazon started as an online bookseller 20 years ago. Since then, it has evolved into a technology juggernaut that has disrupted multiple markets and industries and touches many aspects of our lives. It is a relentless technology and business model innovator driving disruption throughout numerous ecosystems. Amazon’s AWS revenues alone are approaching $16B a year making it one of the largest IT companies in the world. With dominant offerings in Cloud, IoT, eCommerce, Big Data, AI, Digital Assis...
SYS-CON Events announced today that delaPlex will exhibit at SYS-CON's @CloudExpo, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. delaPlex pioneered Software Development as a Service (SDaaS), which provides scalable resources to build, test, and deploy software. It’s a fast and more reliable way to develop a new product or expand your in-house team.
In order to meet the rapidly changing demands of today’s customers, companies are continually forced to redefine their business strategies in order to meet these needs, stay relevant and continue to see profitable growth. IoT deployment and development is integral in this transformation, and today businesses are increasingly seeing the value of investing their resources into IoT deployments. These technologies are able increase ROI through projects such as connecting supply chains or enabling sm...
SYS-CON Events announced today that Cloudistics, an on-premises cloud computing company, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloudistics delivers a complete public cloud experience with composable on-premises infrastructures to medium and large enterprises. Its software-defined technology natively converges network, storage, compute, virtualization, and management into a ...
New competitors, disruptive technologies, and growing expectations are pushing every business to both adopt and deliver new digital services. This ‘Digital Transformation’ demands rapid delivery and continuous iteration of new competitive services via multiple channels, which in turn demands new service delivery techniques – including DevOps. In this power panel at @DevOpsSummit 20th Cloud Expo, moderated by DevOps Conference Co-Chair Andi Mann, panelists will examine how DevOps helps to meet th...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
Every successful software product evolves from an idea to an enterprise system. Notably, the same way is passed by the product owner's company. In his session at 20th Cloud Expo, Oleg Lola, CEO of MobiDev, will provide a generalized overview of the evolution of a software product, the product owner, the needs that arise at various stages of this process, and the value brought by a software development partner to the product owner as a response to these needs.
SYS-CON Events announced today that A&I Solutions has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Founded in 1999, A&I Solutions is a leading information technology (IT) software and services provider focusing on best-in-class enterprise solutions. By partnering with industry leaders in technology, A&I assures customers high performance levels across all IT environments including: mai...