Welcome!

@ThingsExpo Authors: Carmen Gonzalez, Yeshim Deniz, Elizabeth White, Pat Romanski, Ruxit Blog

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
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
Bert Loomis was a visionary. This general session will highlight how Bert Loomis and people like him inspire us to build great things with small inventions. In their general session at 19th Cloud Expo, Harold Hannon, Architect at IBM Bluemix, and Michael O'Neill, Strategic Business Development at Nvidia, discussed the accelerating pace of AI development and how IBM Cloud and NVIDIA are partnering to bring AI capabilities to "every day," on-demand. They also reviewed two "free infrastructure" pr...
Have you ever noticed how some IT people seem to lead successful, rewarding, and satisfying lives and careers, while others struggle? IT author and speaker Don Crawley uncovered the five principles that successful IT people use to build satisfying lives and careers and he shares them in this fast-paced, thought-provoking webinar. You'll learn the importance of striking a balance with technical skills and people skills, challenge your pre-existing ideas about IT customer service, and gain new in...
SYS-CON Events announced today that Hitrons Solutions will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Hitrons Solutions Inc. is distributor in the North American market for unique products and services of small and medium-size businesses, including cloud services and solutions, SEO marketing platforms, and mobile applications.
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develop...
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
In his session at @ThingsExpo, Steve Wilkes, CTO and founder of Striim, will delve into four enterprise-scale, business-critical case studies where streaming analytics serves as the key to enabling real-time data integration and right-time insights in hybrid cloud, IoT, and fog computing environments. As part of this discussion, he will also present a demo based on its partnership with Fujitsu, highlighting their technologies in a healthcare IoT use-case. The demo showcases the tracking of patie...
Almost two-thirds of companies either have or soon will have IoT as the backbone of their business. Though, IoT is far more complex than most firms expected with a majority of IoT projects having failed. How can you not get trapped in the pitfalls? In his session at @ThingsExpo, Tony Shan, Chief IoTologist at Wipro, will introduce a holistic method of IoTification, which is the process of IoTifying the existing technology portfolios and business models to adopt and leverage IoT. He will delve in...
SYS-CON Events announced today that Outlyer, a monitoring service for DevOps and operations teams, 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. Outlyer is a monitoring service for DevOps and Operations teams running Cloud, SaaS, Microservices and IoT deployments. Designed for today's dynamic environments that need beyond cloud-scale monitoring, we make monitoring effortless so you...
Unsecured IoT devices were used to launch crippling DDOS attacks in October 2016, targeting services such as Twitter, Spotify, and GitHub. Subsequent testimony to Congress about potential attacks on office buildings, schools, and hospitals raised the possibility for the IoT to harm and even kill people. What should be done? Does the government need to intervene? This panel at @ThingExpo New York brings together leading IoT and security experts to discuss this very serious topic.
It is one thing to build single industrial IoT applications, but what will it take to build the Smart Cities and truly society changing applications of the future? The technology won’t be the problem, it will be the number of parties that need to work together and be aligned in their motivation to succeed. In his Day 2 Keynote at @ThingsExpo, Henrik Kenani Dahlgren, Portfolio Marketing Manager at Ericsson, discussed how to plan to cooperate, partner, and form lasting all-star teams to change the...
The buzz continues for cloud, data analytics and the Internet of Things (IoT) and their collective impact across all industries. But a new conversation is emerging - how do companies use industry disruption and technology enablers to lead in markets undergoing change, uncertainty and ambiguity? Organizations of all sizes need to evolve and transform, often under massive pressure, as industry lines blur and merge and traditional business models are assaulted and turned upside down. In this new da...
“We're a global managed hosting provider. Our core customer set is a U.S.-based customer that is looking to go global,” explained Adam Rogers, Managing Director at ANEXIA, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
WebRTC services have already permeated corporate communications in the form of videoconferencing solutions. However, WebRTC has the potential of going beyond and catalyzing a new class of services providing more than calls with capabilities such as mass-scale real-time media broadcasting, enriched and augmented video, person-to-machine and machine-to-machine communications. In his session at @ThingsExpo, Luis Lopez, CEO of Kurento, introduced the technologies required for implementing these idea...
In an era of historic innovation fueled by unprecedented access to data and technology, the low cost and risk of entering new markets has leveled the playing field for business. Today, any ambitious innovator can easily introduce a new application or product that can reinvent business models and transform the client experience. In their Day 2 Keynote at 19th Cloud Expo, Mercer Rowe, IBM Vice President of Strategic Alliances, and Raejeanne Skillern, Intel Vice President of Data Center Group and G...
Financial Technology has become a topic of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 20th Cloud Expo at the Javits Center in New York, June 6-8, 2017, will find fresh new content in a new track called FinTech.
@GonzalezCarmen has been ranked the Number One Influencer and @ThingsExpo has been named the Number One Brand in the “M2M 2016: Top 100 Influencers and Brands” by Onalytica. Onalytica analyzed tweets over the last 6 months mentioning the keywords M2M OR “Machine to Machine.” They then identified the top 100 most influential brands and individuals leading the discussion on Twitter.
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
Manufacturers are embracing the Industrial Internet the same way consumers are leveraging Fitbits – to improve overall health and wellness. Both can provide consistent measurement, visibility, and suggest performance improvements customized to help reach goals. Fitbit users can view real-time data and make adjustments to increase their activity. In his session at @ThingsExpo, Mark Bernardo Professional Services Leader, Americas, at GE Digital, discussed how leveraging the Industrial Internet and...
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.