What do we do when elements appears as uncomplied/raw elements before page is rendered (like a blink or flicker) in angular Js (Angularjs – ng-cloak/ng-show elements blink)?
To prevent the Angular HTML template from being displayed by the browser in uncompiledform while your application is loading, we use the ngCloak directive.
Adding the “display: none” property to the CSS might not be enough to stop the flickering / blink of the elements.If you are loading angular.js in the body the templates aren’t compiled soon, so to prevent the blink we can use the ng-cloak directive and include the following in your CSS:
Many Backend developers make great use of various application frameworks out there.Given the various kinds of backend frameworks available, web developers have options as to which type of framework they would like to interact from UI standpoint or any frontend framework for that matter. Though there are many frameworks that are very popular some time ago but it becomes more untrendy while the popularity of AngularJS rapidly grows.
As the User Interface is completely moving to the client-side (browser-based), the server-side logic becomes simpler. Moreover, back-end folks (server-side developers) do not have to worry about how to build HTML pages using templates to generate the dynamic content. Rather, they may focus more on optimizing business logic and data persistence using Datastore access and OAuth2 authentication – which then can be exposed as services to client-side.
To better understand the dominance of Angular JS, let’s explore in deep to outline and know why it has become the future wave in developers perspective.
How Java developers are seeing Angular?
AngularJS is mostly popular among companies that builds applications on Java Stack because it makes lots of things easy. After experimenting different javascript frameworks and libraries, most of the Java developers decided to stick with Angular JS. The learning curve of AngularJS is not too steep for Java developers, when it comes to understanding the concepts of containers, dependency injections,and callbacks. They find some similarities in Angular because of their background in Spring/Hibernate. They may have to become more proficient with JavaScript functions, closures and other ‘good’ stuff. But equally important is to be familiar with today’s tooling of a productive Web developer.
Also, JSF and JSP are two technologies that have been widely used to communicate and interact with application up until now. They have been using Java server to exchange the JSON-formatted data with a single-page HTML/JavaScript front end treating the browser only as a rendering platform with no state. Later many moved to other frameworks like AngularJS, as it does most of the stuff Ajax does, and browser technologies were not something that could be avoided, rather used to full capacity to build a ‘client-app’’ than mere ‘web page’.. So many Java Developers started to utilize Angular similar to the power and ease of JSF’s server side data binding, while still being able to unleash the power of client side Javascript.
AngularJS and .NET Developers:
Creating single page apps with Angular and ASP.Net gives developers a great start. Both of them together are compatible to MVC framework with the only difference being, while one is a client side validation (AngularJS) the other favors server side validation (ASP.Net). Senior developers are excited to use AngularJS to make more responsive client side applications with a clear Separation of Concerns (SoC). Many of them are excited to leverage the combination of AngularJS and MVC in order to provide amazing user experiences.
PHP/Python developers view on AngularJS:
Most PHP & Python developers know some level of Angular JS and are in favor of using a Angular MVC framework. Angular MVC frameworks are used for rapid development, many include templating engines which allow PHP developers to create a single page layout which will load different content depending on what page you have visited. Many PHP/Python developers agree that if they are building an application with AngularJS, they must focus on using Angular client-side templates and stay away from server-side templates to avoid incorrect rendering (with Flask/Jinja templates interruption).
Learning curve:
Although AngularJS seemed to be quite new initially, it stood out from the rest with its extensive documentation, its two-way binding, built-in support for unit testing, and clean MVC implementation. Additionally, it lets developers get things done with minimal amount of JavaScript. Many feel AngularJS to be really easy to get started with its new features coming up with and few find it bit difficult when coming from other programming backgrounds. But fortunately, all the tools are quite easy to use along with being lightweight and agile.
Angular attention:
Angular has got huge adoption and fervent support from the community. It gets developers excited on developer productivity, simplicity and clearness in getting things done,without having to spend hours writing a graphical user interface entirely from scratch.
What’s the correct way to communicate between controllers in AngularJS?
The two best ways to communicate between controllers in Angular JS are:
a) $broadcast
b) $emit
$emit, $broadcast and $on all these methods come under the common “publish/subscribe” design pattern.If an event is fired up the $scope, it is because of $scope.$emit. If an event is fired down the $scope, it is because of $scope.$broadcast. If we want to listen for these events, then we use $scope.$on.
We need not fire events on $rootScope, unless and until we need each and every single scope in the application to be notified about the event, So accordingly, $broadcast method is fired on our own scope only if it required for the children scopes. And if it is required for parent scopes, then $emit is fired on your own scope.
In Angular, a scope is associated to an element, while an element is not necessarily directly associated with a scope. It is important to have a solid understanding of prototypical inheritance and differentiate the types of scopes. A child scope normally (prototypically) inherits from its parent scope, but not always. Scope inheritance is also normally straightforward, until 2-way data binding is required (i.e., ng- model) in the child scope. In that case, the child scope gets its own property that hides/shadows the parent property of the same name.
There are four types of scopes. The first one has “normal prototypical scope inheritance”; ng- include, ng-switch, ng-controller – create new scopes and inherit prototypically ( note that, ng- controller, however, is considered bad form for two controllers to share information via “scope inheritance.”), directive with scope: true. If more than one directive (on the same DOM element) requests a new scope, only one new child scope is created. Since we have “normal” prototypal inheritance, you want to be wary of 2-way data binding to parent scope primitives, and child scope hiding/shadowing of parent scope properties.
The second type has “normal prototypal scope inheritance with a cop y/assignment” – ng-repeat. Each item/ iteration of ng-repeat creates a new child scope, and that new child scope always gets a new property. Changing the child scope property’s value does not change the array the parent scope references.
The third type of scope and the one exception to the rule of inheritance is an “isolate scope” (created by directive with scope: {…}. Note, also, that, by default, directives do not create new scopes i.e., the default is scope: false so there is no inheritance there. Default is not a good choice for writing directives that are intended as reusable components.) An “isolate scope” is not prototypical but ‘=’, ‘@’, and ‘&’ provide a mechanism to access parent scope properties, via attributes. The object hash is used to set up two-way binding (using ‘=’) or one-way binding (using ‘@’) between the parent scope and the isolate scope. There is also ‘&’ to bind to parent scope expressions. So, these all create local scope properties that are derived from the parent scope. This construct is often the best choice when creating a “reusable component” directive, since the directive cannot accidentally read or modify the parent scope.
The last type is a “transcluded scope”- directive with transclude: true. The directive creates a new “transcluded” child scope, which prototypically inherits from the parent scope. The transcluded and the isolated scope are siblings – the $parent property of each scope references the same parent scope.
It’s important to remember that for all scopes (prototypal or not), Angular always tracks a parent- child relationship (i.e., a hierarchy), via properties $parent and $$ childHead and $$childTail.
In the case of a more complex scope inheritance, your workarounds should include three basic steps: 1) define objects in the parent for your mode, then reference a property of that object in the child: parentObj.someProp, 2) use $parent.parentScopeP roperty (where possible), and 3) define a function on the parent scope, and call it from the child.
It’s March 2015 and the AngularJS is hotter than ever. According to our statistics alone 60% of developers are adopting the Google brain child. Hiring rate in AngularJS has gone up to 42% in 2015, compared with 13% in 2012. Now before you start your relationship with this beautiful client-side framework, you want to understand its peculiarities to see if you’d want to spend hours on end playing with it. Let’s say that you’re an active jQuery developer and you’d like to switch to AngularJS – you’re wondering what it’d be like.
Well, the first thing you have to have in mind is that AngularJS and jQuery are pretty much like apples and oranges. They do different things and adopt different ideologies. Technically speaking, jQuery is a library and AngularJS is a framework. In the community, there isn’t even a common word to describe them together- library, platform, framework? There is definitely a common ground here; it’s just not on the surface. Let’s dive deeper into this.
AngularJS provides you with a set of features to produce a web applications, while jQuery mainly gives the ease of DOM manipulation and AJAX. With jQuery you instruct the DOM about what needs to happen step by step. With AngularJS you describe what end result you’d like to see but not how to do it. And here comes first piece of advice : In AngularJS you have to start from the ground up with your architecture in mind. Start with your objective, then move to designing your application flow, followed by data design and then finalize by designing your view for presentation. Your kind of need to plan out the whole project, you can’t just add AngularJS on top. Basically, don’t augment jQuery with AngularJS. If you observe keenly, we planned out to create Data Objects (Models), Behavior and Flow of Application (Controller) and Presentation (View) – making us think in terms of MVC – that’s what AngularJS is mainly about.
(Note: You could rewrite/inject a jQuery plugin in AngularJS but don’t make it your primary solution or you’ll never master AngularJS.)
Ok, so now you know that you need to operate like a server-side developer in addition to thinking like a client-side developer. Now you have to think about how to divide your application into individual, testable components.
Angular allows you to separate/isolate the DOM manipulation in the directives(directives can be considered extensions of HTML – in case HTML doesn’t do something you need.
These directives tell the AngularJS HTML compiler how to behave and what to do (attaching event listeners and interactions). And that is a key differentiator of the framework. If you want, you can create your own custom directives that will contain all your view logic or DOM manipulation. In contrast, jQuery says very little about how you should organize your code. It is you who have to tell the DOM what to do. Let’s break it down:
In jQuery, we programmatically change the view by responding to events and then updating them. AngularJS, on the other hand, will automatically update (synchronize) your view so you don’t have to. The view here is the “official record” of view-based functionality. So outside of a directive (applied in the view) you never need change the DOM.
Let’s repeat again:
Only do DOM manipulation in a directive.
However, in AngularJS there is a separate model layer that is independent from the view that we can manage how we want. Your model represents(or holds) your data and is tied to a view via scopes. Views therefore are a projection of the model. You can create HTML templates for each view, using the directives.
EXAMPLE
Angular.module(“mySampleApp”,[])
.directive(“paymentform”,function(){
return{
restrict: “E”,
templateUrl: “partials/paymentForm.tmpl.html”
}
});
AngularJS also uses directives and controllers (your controller’s function is to initialize $scope) to remove certain behaviors from HTML.
When looking for a comprehensive all-in-one solution, many tech enthusiasts realized that AngularJS is the right choice between the two. Its two-way data binding, in-built directives and filters has allowed developers to build applications very rapidly and has made them think about Angular.js as a viable replacement to jQuery.
Technology trends are increasingly growing today with the developers building robust and more complex applications. Almost all of the rich web applications that we currently see on the web rely on a subtle set of UI controls, libraries and frameworks. There are so many options out there to provide a consistent, reliable, and highly interactive user interface, but selecting the right library or a framework can be overwhelming. To have an idea of all the possible alternatives, in this article we will explore what constitutes best practices with regard to jQuery and, furthermore, why angular is a good choice of a framework to implement.
jQuery as we all know it has become an essential library when it comes to common functions and adding JavaScript functionality to a website. But when it comes to some of the web applications that are large and complex, jQuery alone cannot be used to provide a stable foundation to write quality, maintainable code. Consequently, MVC frameworks have emerged to provide more structured and maintainable code when developing these applications.
There are many JavaScript frameworks, which provide a solid structure for your code whilst also offering some extra functionality to turn up the desired task quickly. To name a few- Angular.js, Backbone.js, EmberJS, KnockoutJS, etc. all these frameworks have their own perspectives based on the functionality, features, size, dependencies and interoperability. Based on the statistical reports of Infoq.com, it is found that AngularJS has been the preferable framework in most of the cases. Also Angular has jQuery dependency, which makes it a good choice for web development. Angular provides a ready framework that works with multiple libraries which can be added on as required.
Let say, if you would like to send some requests to a backend server and display the results on a web page and vice versa. We can perform this simply in both Angular and jQuery. But with Angular it goes really well against jQuery with one big difference. It does not involve us to think of the back and forth DOM translations as opulent to jQuery. In jQuery, the view and the logic or behavior which affects those elements is left to the developer to split them. In jQuery, if we wish to update a specific DOM element with backend data it has to be coded. There is no separation as to which is the data and which is the controller of the data.
That’s where AngularJS comes into play with its two way data binding. Angular separates the UI data and the UI representation of data. The code in AngularJS is the translation of data to the DOM and vice versa. Angular makes this binding ideal, while increasing productivity. This is the best way to separate data and the HTML view code.
Angular provides rich ‘desktop like’ applications and features that you don’t get with using a jQuery library.
MVW pattern (similar to MVC)
Two way data binding
Dependency Injection:
Templates
Form Validations
Deep Linking for dynamic pages
Communication with server
Reusable components and localization to name a few
When looking for a comprehensive all-in-one solution, AngularJS is the right choice between the two. Its two-way data binding, in-built directives and filters allows developers to build applications very rapidly. So if you are looking for a lightweight and modular front-end framework for developing fast and powerful web interfaces, AngularJS is the apt framework to build complex applications. I hope this post has made you think about Angular.js as being a more than viable replacement to jQuery.
