Welcome!

Java IoT Authors: Stackify Blog, APM Blog, Liz McMillan, Elizabeth White, Yeshim Deniz

Related Topics: Java IoT, Agile Computing, @ThingsExpo

Java IoT: Blog Feed Post

Angular 2: Passing Data to Routes By @YFain | @ThingsExpo #IoT

Angular offers a directive RouteParams so a route can receive data from the parent component

In the previous blog I did a high-level overview of Angular 2 router and wrote a basic routing application that demonstrated displaying different components in a predefined area of the window. We often need not only display a component, but also pass some data to it.

For example, if we navigate from the Home to the Product Detail route we need to pass the product ID to the destination route. Angular offers a directive RouteParams so a route can receive data from the parent component. There is also a RouteData directive that can be used to pass additional data to a route from the @RouteConfig section. I’ll illustrate the use of both directives by modifying the app from the previous blog.

Using RouteParams
When the user navigates to the ProductDetail route, we need to pass the product ID to display details of the particular product. Let’s modify the code so the RootComponent can pass the product ID to ProductDetailComponent. The new version of this component will be called ProductDetailComponentParam and it’ll use the directive RouteParams:

import {Component} from 'angular2/angular2';
import {RouteParams} from 'angular2/router';

@Component({
selector: 'product',
template: `<h1 class="product">Product Detail for Product: {{productID}}</h1>` , // 1
styles: ['.product {background: cyan}']})
export class ProductDetailComponentParam {
productID: string;
constructor(params: RouteParams) { // 2
this.productID = params.get('id'); // 3
}

  1. Display the received product ID using binding.
  2. The constructor of this component requests Angular to inject the object RouteParams, which contains all parameters that are passed to this component. In TypeScript you just need to declare the argument specifying its type, and Angular will know how to instantiate and inject this object. We’ll cover dependency injection in details in Chapter 5.
  3. Get the value of the parameter named id and assign it to the class variable productID, which is used in template via binding.

Now let’s see how we can change @RouteConfig and router-link to ensure that the value of the product ID will be passed to the component ProdutDetailComponentParam if the user choses to go this route. We’ll do the changes in the file main.ts:

import 'reflect-metadata';
import 'zone.js'; // 1

import {Component, bootstrap, provide} from 'angular2/angular2';
import {HomeComponent} from './components/home'; // 2
import {ProductDetailComponentParam} from "./components/product_param";

import {RouteConfig, ROUTER_DIRECTIVES, ROUTER_PROVIDERS,
LocationStrategy, HashLocationStrategy} from 'angular2/router';

@Component({
selector: 'basic-routing',
template: `<a [router-link]="['/Home']">Home</a>
<a [router-link]="['/ProductDetail', {id: 1234}]">Product Details</a> // 3
<router-outlet></router-outlet>`,
directives: [ROUTER_DIRECTIVES]})
@RouteConfig([
{path: '/', component: HomeComponent, as: 'Home'},
{path: '/product/:id', component: ProductDetailComponentParam, as: 'ProductDetail' }]) // 4
class RootComponent {}

bootstrap(RootComponent, [ROUTER_PROVIDERS,
provide(LocationStrategy, {useClass: HashLocationStrategy})]);

  1. Angular asynchronously modifies the values of properties participated in binding. In our case, after the user choses to open the product detail component, the value of the variable productID changes and its bindings need to be updated. The library zone.js will automatically sync up all the bindings and watchers in the entire component tree of the application.
  2. I kept my components in the _components_ directory and need import them from there.
  3. This time there are two elements in the array given to router-link. The first one is the name of the route and the second is a JavaScript object containing a name/value pair that represents the parameter to be passed to the /ProductDetail route. For simplicity we’ve hardcoded the id to be 1234, but if we had a variable product pointing to the corresponding object, we could have written {id: product.id} here.
  4. The path property has an additional fragment /:id. The name of this URL fragment must match the name of the parameter property used in router-link. Angular will construct the URL fragment /product/1234 for this ProductDetail route. Note that we still use the same route name in router-link even though it points not to the ProductDetailComponent but to ProductDetailComponentParam.

The following screenshot shows how the product detail view will be rendered in the browser:

ch4_basic_routing_product_detail_param

Note the URL. Angular router replaced the path /product/:id with /product/1234.

Let’s overview the steps that Angular did under the hood for rendering the main page of the application:

  1. Check the the content of each router-link to find the corresponding routes configurations.
  2. Modify the URL fragments the parameters with actual values where specified.
  3. Build the actual <a href=””> tags that the browser understands.

The next screenshot shows a snapshot of the home page of our application with the Chrome Dev Tools panel open.

ch4_basic_routing_product_detail_href

Since the path property of the Home route contains just the slash, Angular simply removed it – a single slash base URL of the page. But the anchor under Product Details link is already converted into a regular HTML tag. When the user will click on the Product Details link, the router will attach a hash sign and add /product/1234 to the base URL so the absolute URL of the Product Detail view will become http://localhost:8080/#/product/1234.

Using RouteData
While most of the times parent components will be passing data to their children, Angular also offers a mechanism to pass additional data to components at the time of the route configuration. For example, besides the data that a component needs for implementing application logic, we may need to pass a flag indicating if the application runs in production environment or not. This can be done by using the data property of the @RouteConfig annotation. For example, our ProductDetail route can be configured as follows:

@RouteConfig([
{path: '/product/:id', component: ProductDetailComponentParam,
as: 'ProductDetail', data: {isProd: true}}])

Accordingly, the constructor of the ProductDetailComponent will need an extra argument of type RouteData:

export class ProductDetailComponentParam {
productID: string;
constructor(params: RouteParams, data: RouteData) {
this.productID = params.get('id');

console.log(`Is this prod environment: ${data.get('isProd')}`);
}
}

Passing data to a route with RouteData is not an alternative to RouteParams. While RouteParams is used to pass the data from one route to another using based on the user’s selections (e.g., show details of the selected product), RouteData can come handy when you need to pass some data to a route during the configuration phase, e.g. is it a production or QE environment, should the user have administrator’s privileges, or what URL of use for the product service.

To see this application in action follow this plank and press the button Run. For simplicity, all the code is located in one file main.ts. Also, I imported the dev version of Angular in the index.html that includes such libraries as zone.js and reflect-metadata, so there is no need to import them separately.

Stay tuned for more Angular 2 blogs. My other Angular-related blogs are here . Manning started publishing drafts of our book “Angular 2 Development with TypeScript“.

Read the original blog entry...

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
In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
"There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Large industrial manufacturing organizations are adopting the agile principles of cloud software companies. The industrial manufacturing development process has not scaled over time. Now that design CAD teams are geographically distributed, centralizing their work is key. With large multi-gigabyte projects, outdated tools have stifled industrial team agility, time-to-market milestones, and impacted P&L stakeholders.
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
"Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"MobiDev is a software development company and we do complex, custom software development for everybody from entrepreneurs to large enterprises," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
"Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
It is of utmost importance for the future success of WebRTC to ensure that interoperability is operational between web browsers and any WebRTC-compliant client. To be guaranteed as operational and effective, interoperability must be tested extensively by establishing WebRTC data and media connections between different web browsers running on different devices and operating systems. In his session at WebRTC Summit at @ThingsExpo, Dr. Alex Gouaillard, CEO and Founder of CoSMo Software, presented ...
WebRTC is great technology to build your own communication tools. It will be even more exciting experience it with advanced devices, such as a 360 Camera, 360 microphone, and a depth sensor camera. In his session at @ThingsExpo, Masashi Ganeko, a manager at INFOCOM Corporation, introduced two experimental projects from his team and what they learned from them. "Shotoku Tamago" uses the robot audition software HARK to track speakers in 360 video of a remote party. "Virtual Teleport" uses a multip...
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...
SYS-CON Events announced today that Evatronix will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Evatronix SA offers comprehensive solutions in the design and implementation of electronic systems, in CAD / CAM deployment, and also is a designer and manufacturer of advanced 3D scanners for professional applications.
Leading companies, from the Global Fortune 500 to the smallest companies, are adopting hybrid cloud as the path to business advantage. Hybrid cloud depends on cloud services and on-premises infrastructure working in unison. Successful implementations require new levels of data mobility, enabled by an automated and seamless flow across on-premises and cloud resources. In his general session at 21st Cloud Expo, Greg Tevis, an IBM Storage Software Technical Strategist and Customer Solution Architec...
To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
An increasing number of companies are creating products that combine data with analytical capabilities. Running interactive queries on Big Data requires complex architectures to store and query data effectively, typically involving data streams, an choosing efficient file format/database and multiple independent systems that are tied together through custom-engineered pipelines. In his session at @BigDataExpo at @ThingsExpo, Tomer Levi, a senior software engineer at Intel’s Advanced Analytics gr...
When talking IoT we often focus on the devices, the sensors, the hardware itself. The new smart appliances, the new smart or self-driving cars (which are amalgamations of many ‘things’). When we are looking at the world of IoT, we should take a step back, look at the big picture. What value are these devices providing? IoT is not about the devices, it’s about the data consumed and generated. The devices are tools, mechanisms, conduits. In his session at Internet of Things at Cloud Expo | DXWor...