The competition among frontend frameworks

 Frontend frameworks for desktop and responsive on other devices can be categorized in 5 main types:

• Angular
• ReactJS/Nextjs
• VueJS
• Classic (html, css, jquery, thymeleaf, asp.net)
• Flutter Web
  

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VUE3 for Java developer

What is Vue.js and VUE 3 features?

Vue (pronounced /vjuː/, like view) is a progressive framework for building user interfaces. Unlike other monolithic frameworks, Vue is designed from the ground up to be incrementally adoptable. The core library is focused on the view layer only, and is easy to pick up and integrate with other libraries or existing projects. On the other hand, Vue is also perfectly capable of powering sophisticated Single-Page Applications when used in combination with modern tooling and supporting libraries (opens new window)

Vue 3 was officially released on September 18, 2020. While it has some great new features, especially having full TypeScript support which is the same as Angular 10. New Features in Vue 3 are

•     Composition API (built-in now)
•     Full TypeScript support
•     Portals
•     Fragments
•     Suspense
•     Global Mounting/Configuration API change
•     Multiple v-models
•     Custom Directive API
•     Multiple root elements (Template syntax )
•     Better reactivity
•     Emits Component Option

Easy integration is one important feature of VUE so that It is now easy to integrate with java frameworks such as Apache wicket, Play framework, Spring framework.. Java backend developer can be easy to understand VUE 3 so that they will improve their weakness with frontend.

Some VUE 3 details

The Composition API is introduced in Vue 3 as an alternative to the Options API in vuejs 2.x. 

It would be much nicer if we could collocate code related to the same logical concern. And this is exactly what the Composition API enables us to do. To start working with the Composition API we first need a place where we can actually use it. In a Vue component, we call this place the setup.

The setup option should be a function that accepts props and context which we will talk about later. Additionally, everything that we return from setup will be exposed to the rest of our component (computed properties, methods, lifecycle hooks and so on) as well as to the component's template. The setup method is also where all the action happens. This method gets called after beforeCreate and right before the created lifecycle hooks. Notice that setup is the only function inside our component.  

beforeCreate() => setup() => create()




For example:

import {defineComponent, ref, computed} from 'vue';

export default defineComponent({

  name: 'HelloNewYear',

  components: {},

  props: {

    msg: Object,

  },

  setup(props) {

      const msg = ref('msg');      

      const updateMsg = (newValue) => msg.value = newValue;

  

      return { msg, updateMsg }

  }

});

Lifecycle inside setup() includes 9 lifecycles:

•     onBeforeMount
•     onMouted
•     onBeforeUpdate
•     onUpdated
•     onBeforeUnmount
•     onUnmount
•     onActivated
•     onDeactivated
•     onErrorCaptured
•     onRenderTracked
•     onRenderTriggered

Full TypeScript support

Vue 3 has full TypeScript support. For example, 

To create mixins in TypeScript, we must first create our mixin file, which contains the data we share with other components.

Create a file called MsgMixin.ts inside the mixins directory and add the following mixin, which shares the project name and a method to update the project name.

import { Component, Vue } from 'vue-property-decorator'
@Component
class MsgMixin extends Vue {
  public msgName: string = 'My Message
  public setMsgName(newVal: string): void {
    this.msgName = newVal
  }
}
export default MsgMixin

Multiple root elements (template syntax )

In Vue 2,  the template tag can only take one root element. In Vue 3, There is no need for a root element anymore.

We can use any number of tags directly inside the <template></template> section:

<template>

  <p> Count: {{ count }} </p>

  <button @click="increment"> Increment </button>

  <button @click="decrement"> Decrement</button>

</template>

Equivalent code in Vue 2:

<template>

  <div class="counter">

    <p> Count: {{ count }} </p>

    <button @click="increment"> Increment </button>

    <button @click="decrement"> Decrement</button>

  </div>

</template>

Suspense

Suspense is a special component that renders a fallback content instead of your component until a condition is met. 

Provide / inject

In Vue 2, we used props for passing data – such as string, arrays, objects, and so on – from a parent component directly to its children component. But in many cases, we also need to pass data from the parent component to a deeply nested child component which is, not so appropriate and becoming complicated in normal cases.

Vue 3 use the new Provide and inject pair to pass data with vuex.

Teleport is a new feature that makes it easy to display a component outside its default position i.e the #app container where Vue apps are usually wrapped. You can, for example, use Teleport to display a header component outside the #app div. Please note that you can only Teleport to elements that exist outside of the Vue DOM.

Global Mounting/Configuration API Change

It has simple command as following

import { createApp } from 'vue'

import App from './App.vue'

const app = createApp(App)

app.config.ignoredElements = [/^app-/]

app.use(/* ... */)

app.mixin(/* ... */)

app.component(/* ... */)

app.directive(/* ... */)

app.mount('#app')

Multiple v-Models

for example, to bind and listen to multiple properties in components:

<NameComponent

  v-model:fornames="forname"

  v-model:surname="surname"

/>

Understanding Vue 3 Ref for Reactive Variables

In this section, we'll learn about the ref() function in Vue 3. In Vue 3, you can use the ref() function to define a reactive variable. It can wrap any primitive or object and return it’s reactive reference. The value of passed element will be kept in a value property of the created reference. For example if you want to access value of count reference you need to explicitly ask for count.value. 

Difference between Angular and Vue on Different Parameters

Parameters	ANGULAR	VUE
Easy Integration	Angular is a Javascript framework, making easier for developers to integrate it with third-party components and other Javascript-based technologies.	On the other hand, Vue is a versatile and a flexible framework. It facilitates front-end libraries integration easily.
Flexibility	Angular framework is considered highly flexible as it offers official support to multiple systems without any restriction.	At the same time, Vue is not as flexible as Angular. It's a bit rigid. There are some rules which need to be followed while working on an application. Still, it provides flexibility for modular solutions.
Complexity	Angular framework is much more complex than Vue when it comes to design and API. A non-trivial application development takes more time with Angular than Vue.	Developing a non-trivial application takes less time when integrating with Vue. If we talk about design and API, Vue is considered simpler.
TypeScript	The learning resources provided by Angular are Typescript based so it acts as a booster for the developers and at the same time difficult for the beginners to learn.	Vue recently got the Typescript functionality, but it is not currently in use.
Performance	Angular has performed well till date. It doesn't disappoint. Angular is best known for its fast performance. Despite having a lot of watchers, Angular guarantee the same performance metrics on different platforms.	Vue also delivers the same quality performance as Angular. Both of them perform outstandingly on different benchmarks and at the same time addressing similar issues.
Data binding	Angular utilizes a two-way binding process between scopes. In addition to this, it supports asynchronous services to assist developers when they develop third-party components to integrate with the app.	On the other hand, Vue supports one-way data flow between the components. It facilitates non-trivial app development quickly.

VUE 3 and Angular are both using TypeScript and html/css template opposed to ReactJS that uses HTML (JSX) inside JavaScript.

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Angular 2 with ZK

With the emerging of reactjs and angular2, zk and other old ui java frameworks are standing before of going to history library but now angular2 has been integrated into zk and make it having more custom chosen for users so that zk framework is still used for maintainance and new java projects.

Angular 2 is integrated in zk by using  client command binding to communicate with a Java ViewModel at the server-side.

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Spring Boot + React Redux and MySQL CRUD example

This article will build React Redux Http Client & Spring Boot Server example that uses Spring Data JPA to interact with MySQL database and React as a front-end technology to make request and receive response.
Technologies
– Java 1.8
– Maven 3.3.9
– Spring Tool Suite 3.9.0.RELEASE
– Spring Boot 2.0.1.RELEASE
– Webpack 4.4.1
– React 16.3.0
– Redux 3.7.2
– React Redux 5.0.7
– axios 0.18.0
– MySQL 5.7.16

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Devstack download: migrating from JSF to ReactJS

At Bandwidth, our UI front end was originally written using JSF (java server faces). This made sense at the time because we had a lot of Java developers and it was easier for them to work with. As time moved on and we expanded our team we got more front-end developers on board. They were pushing for a more modern front end stack that will help improve efficiency for front-end development. That is how we ended up deciding to use ReactJs.
I think one of the trickiest parts of the change was deciding how to go about it. It takes a lot of time and effort to make the change and we had to convince everyone that it would be worth it. Since there was already a movement to revamp our signup process, it seemed like a perfect opportunity to write that using ReactJs and Redux. It also had the plus side of not needing to be authenticated so you really couldn’t pick a better piece to migrate first. You can click the link below to check out our new signup page and see the results!

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Announcing the Ionic React Beta

How to Get Started with React & Ionic?

Getting started is quite simple. Begin first with create-react-app, because we want you to use Ionic with React in the most familiar way. We also recommend using TypeScript in your app, something we recently wrote about on our blog if you need tips. While this is not required, we mention it because Ionic React ships with TypeScript type definitions, and it makes for an excellent developer experience.

 npx create-react-app my-ionic-app --typescript
 cd my-ionic-app

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Angular in Netbeans IDE

Requirements:

• Netbeans IDE 8.2
• Git-2.20.1-64-bit
• npm installed
• netbeanstypescript-2.x.nbm

Run commands:

 npm install -g bower
 npm install -g typescript

Detail at https://www.tutorialjinni.com/angular-2-netbeans-8.2-typescript-hello-world-example.html

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Angular 7 vs React

Angular is a fully-fledged MVC framework and React is simply a JavaScript Library.

Here’s what Angular provides directly out-of-the-box:
-Templates, based on an extended version of HTML
-XSS protection
-Dependency injection
-Ajax requests by @angular/HTTP
-Routing, provided by @angular/router
-Component CSS encapsulation
-Utilities for unit-testing components
-@angular/forms for building forms
-Write once run everywhere

React provides the following “out of the box”:
-Instead of classic templates, it has JSX, an XML-like language built on top of it
-JavaScript
-XSS protection
-No dependency injection
-Fetch for Ajax requests
-Utilities for unit-testing components
-Learn once write anywhere

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React.js and Spring Data REST - Basic Features

Spring Data REST provides backend functionality
React has sophisticated features to build an easy-to-grok UI.

• Spring Data REST provides a fast way to build hypermedia-powered repositories.
• React is Facebook’s solution to efficient, fast, and easy-to-use views in the land of JavaScript.

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MVC vs Flux

Flux is the application architecture that Facebook uses for building client-side web applications. It complements React's composable view components by utilizing a unidirectional data flow. It's more of a pattern rather than a formal framework, and you can start using Flux immediately without a lot of new code.

Flux applications have three major parts: the dispatcher, the stores, and the views (React components). These should not be confused with Model-View-Controller. Controllers do exist in a Flux application, but they are controller-views — views often found at the top of the hierarchy that retrieve data from the stores and pass this data down to their children. Additionally, action creators — dispatcher helper methods — are used to support a semantic API that describes all changes that are possible in the application. It can be useful to think of them as a fourth part of the Flux update cycle.

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Add Kendo UI into Angular Quickstart sample

SystemJS is a dynamic ECMAScript (ES) module loader that is used by Angular Quickstart and other projects.

To use Kendo UI components for Angular with SystemJS, you have to explicitly list the package entry points. This article demonstrates how to implement the required configuration when you use the Angular Quickstart project template.

The source code for the completed sample project is available on GitHub at telerik/kendo-angular-quickstart.

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Beginning Kendo UI

1. What is Kendo UI

Kendo UI is a comprehensive framework which comes with a library of 70+ UI widgets, an abundance of data-visualization gadgets, client-side data source, and a built-in MVVM (Model-View-ViewModel) library. It provides AngularJS and Bootstrap integration and is also distributed as part of several product units that you can choose from depending on your project requirements.
Install kendo ui core for jsp anh html application:

• Step 0 Dowload from https://github.com/telerik/wrappers-getting-started/tree/master/jsp/jsp-episode1/WebContent OR Download full files from download any of the Kendo UI bundles to local computer. 
• Step 1 Extract the /js and /styles directories from the bundle archive and copy them to your web application root directory.
  Step 2 Include the Kendo UI JavaScript and CSS files in the head tag of your HTML document. Verify that the common CSS file is registered before the theme CSS file.
• Step 3 Initialize a Widget.
  The following example demonstrates how to initialize the DatePicker widget.
  

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Beginning React JS

What Is React?

React is a declarative, efficient, and flexible JavaScript library for building user interfaces. It lets you compose complex UIs from small and isolated pieces of code called “components”. React has a few different kinds of components, but we should start with React.Component subclasses

React components implement a render() method that takes input data and returns what to display. It uses an XML-like syntax called JSX but JSX is optional and not required to use React. There are two types of data that control a component: props and state.

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Spring Boot REST + Angular 2 + JPA + Hibernate + MySQL CRUD Example

We will create a REST web service application using Spring Boot and a client application using Angular 2. REST web service will expose methods for create, read, update and delete operation. The Angular application will use Angular Http API for CRUD operation. If our client application is running on different domain from web service domain, then the Spring Boot web service controller will configure client domain URL using @CrossOrigin annotation to handle Cross-Origin-Resource-Sharing (CORS). In our Spring Boot application, we will configure database using application.properties file. To interact with database we will use JPA EntityManager.

There are back-end application using spring-boot rest api and front-end application using Angular 2.

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Connecting your Angular 2 App to your Java EE Backend

1-Introduction

You’ve been developing in Java EE all this time, but you’re tired of using JSF, or perhaps even Struts, and want to move to something more modern for your front end? Angular 2 is a perfect fit, and with the recent release of Angular 2 GA, now is the ideal time to make the move! Besides being easier to develop and maintain, an Angular 2 application allows you to take advantage of the huge improvements in browser technology over the last few years, and all the goodness that the modern web brings.

Broad Strokes

We will be working with two separate applications, a Java EE back-end app, and an Angular 2 front-end app, avoiding a mixing of concerns in a single project. Source for both projects is provided, so in this article we display and highlight source only for key concepts – you can download the projects to look at more detail, or run them locally.

Key technologies:

• JPA: Our sample Java EE application uses JPA to access data from a database.
• REST: We expose the table data via REST web services using Jersey – the reference implementation for the JAX-RS spec.
• RxJS: Our Angular 2 app uses RxJS to communicate with the web services.
  

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HTML attribute vs. DOM property in Angular

1-HTML attribute vs. DOM property

The distinction between an HTML attribute and a DOM property is crucial to understanding how Angular binding works.
Attributes are defined by HTML. Properties are defined by the DOM (Document Object Model).

• A few HTML attributes have 1:1 mapping to properties. id is one example.
  
• Some HTML attributes don't have corresponding properties. colspan is one example.
  
• Some DOM properties don't have corresponding attributes. textContent is one example.
  
• Many HTML attributes appear to map to properties ... but not in the way you might think!
  

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Angular Misc

Observables

Observables provide support for passing messages between publishers and subscribers in your application. Observables offer significant benefits over other techniques for event handling, asynchronous programming, and handling multiple values.
Observables are declarative—that is, you define a function for publishing values, but it is not executed until a consumer subscribes to it. The subscribed consumer then receives notifications until the function completes, or until they unsubscribe.
An observable can deliver multiple values of any type—literals, messages, or events, depending on the context. The API for receiving values is the same whether the values are delivered synchronously or asynchronously. Because setup and teardown logic are both handled by the observable, your application code only needs to worry about subscribing to consume values, and when done, unsubscribing. Whether the stream was keystrokes, an HTTP response, or an interval timer, the interface for listening to values and stopping listening is the same.
Because of these advantages, observables are used extensively within Angular, and are recommended for app development as well.

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Angular Forms

Introduction to forms in Angular

Handling user input with forms is the cornerstone of many common applications. Applications use forms to enable users log in, to update a profile, to enter sensitive information, and to perform many other data-entry tasks.
Angular provides two different approaches to handling user input through forms: reactive and template-driven. Both capture user input events from the view, validate the user input, create a form model and data model to update, and provide a way to track changes.
Reactive and template-driven forms differ, however, in how they do the work of processing and managing forms and form data. Each offers different advantages.
In general:

• Reactive forms are more robust: they are more scalable, reusable, and testable. If forms are a key part of your application, or you're already using reactive patterns for building your application, use reactive forms.
• Template-driven forms are useful for adding a simple form to an app, such as an email list signup form. They are easy to add to an app, but they do not scale as well as reactive forms. If you have very basic form requirements and logic that can be managed solely in the template, use template-driven forms.

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angular components and templates

Displaying Data

The live example / download example demonstrates all of the syntax and code snippets described in this page.

Showing component properties with interpolation

The easiest way to display a component property is to bind the property name through interpolation. With interpolation, you put the property name in the view template, enclosed in double curly braces: {{myHero}}.
When you bootstrap with the AppComponent class (in main.ts), Angular looks for a <app-root> in the index.html, finds it, instantiates an instance of AppComponent, and renders it inside the <app-root> tag.

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Angular2 Architecture Overview

Angular is a framework for building client applications in HTML and either JavaScript or a language like TypeScript that compiles to JavaScript.
The framework consists of several libraries, some of them core and some optional.

You write Angular applications by composing HTML templates with Angularized markup, writing component classes to manage those templates, adding application logic in services, and boxing components and services in modules.
Then you launch the app by bootstrapping the root module. Angular takes over, presenting your application content in a browser and responding to user interactions according to the instructions you've provided.

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