Step-to-step Guide to AngularJS Web Application Development

Hello everyone! Want to develop your own AngularJS web application and don’t know how to start? In this article, I wrote why you should choose AngularJS development framework to develop such applications and all its main features, what steps you need to follow to create a project.

Even beginners will be able to understand this, so let’s go!

AngularJS is one of the most popular builds of tools for creating web applications.

Thanks to its technical potential and open source code, this JavaScript framework allows the programmer to develop a browser application taking into account the smallest details, and built-in simplified testing allows the customer to often receive a ready-made solution ahead of time.

It is worth to say that the functionality of the application is provided by a simplified jQuery library – jqLite, which will allow the user to use any mechanism in managing the DOM tree. The origin of the library was necessary to simplify the process of managing the DOM tree, therefore, its capabilities include traversing the structural elements of documents, playing animation components, processing data or events, performing any interactions using Ajax mechanisms. This is the difference between the library and AngularJS, since this software is a framework that provides control over all aspects of Web 2.0 application development.

The concept behind AngularJS and jQuery is different, but AngularJS is the preferred choice for creating a universal modern web application. In developing an optimal web application, the main aspect is a competent and comprehensive approach to managing the existing mechanisms and structural elements, which will allow you not to waste time and create convenient user interfaces in a short time. 

How to start developing a web application?

  • Define the goals and objectives of the project;
  • Understand who will become your customers;
  • Identify your competitors;
  • Highlight the key features of your product / service;
  • Approve the development cost.

The above steps are suitable for those who have already tried to write at least one application, tested it and received a quality product.

After such a debut, the developer can safely take orders from customers and get a decent pay for their work. And what about newbies? If you spent a big amount of your time studying all the Angular documentation, watched a video on YouTube and took the course, and now you want to try to write your application then read the following. 

To load any Angular application, you need to call the ng-app directive. This directive can be written in any HTML tag, it is used to auto load Angular applications.

Ng-app is the root of an Angular application, and only one Angular application can be run per web page. Basically, almost always, a directive call can be found in the html tag. Now we need to name our application app.

Let’s see how it behaves and add some JS code. But before proceeding, you need to connect the Angular library itself, and our code will be in the app.js file. To add Angular to our project, I used the Bower manager, I configured it to save my components to the / lib folder.

I saved the app.js file in the / app folder. We got the index.html file. Next, we will work in the app.js file. We need to set the initial state of the application.

For this, we will write the code. As you should already know, the square brackets in the installer are responsible for downloading any dependencies that we may need in the dependency injection pattern.

Right now our application does absolutely nothing, let’s create and add the first controller and bind it to the DOM somehow. To declare a new controller in Angular, we simply attach a ‘.controller’ line to our module (controller constructor).

In our case, since we write all the JS code in one file and add what we need. There are a couple of things worth noticing. First, we named our controller AppController, in a similar way we named our base module. Second, we used a string connection to explicitly make it clear that the $ scope variable is a dependency on our controller.

And third, the $ scope variable is fed to the input of the unnamed function, i.e. we make this variable available inside the function, i.e. and for the whole controller. What is this $ scope variable anyway? In Angular, a scope, it is an object associated with the application model and acts as a link between the controller and the view.

The initial state of the scope can be set by attaching various properties to the object. You can also hook methods to the $ scope object.

All properties of the $ scope object will be available in the DOM at the controller declaration level. But how do you declare the controller itself? In the html code, we need some kind of DOM section that will be linked to the controller in such a way that we can actually apply two-way data binding and finally start working with Angular. Recall that our controller is named AppController, so declare the controller in HTML via ng-controller.

Now we have used the second directive, ng-controller. Our AppController is now DOM bound. We are now completely ready! Let’s see a couple of major Angular features in action.

All the code, we will assume, will be inside the controller function. It is recommended to use the word controller in the name of the controller so that it is clear which controller you are referring to in the current template. In our HTML, the output of properties can be done using two brackets.

Refresh the page and voila! You’ve just witnessed two-way data binding in our application.

Let’s go even further, see if we can change the name via click. Angular has another directive called ngClick, with which you can set the behavior of an element when you click on it.

So we gradually learn about the power of Angular, we can bypass all event handlers and use the ngClick directive. Now in our template, you can directly use the ngClick directive and feed it the desired value as input. Below is the HTML code:


<p>Hello, <em>{{ username }}</em>!</p>
<button ng-click=”changeUsername(‘Bob’)”>Hello Bob?</button>
<button ng-click=”changeUsername(‘Adam’)”>Hello Adam?</button>
<button ng-click=”changeUsername(‘Elena’)”>Hello Elena?</button>

When you click on the button, the name will be updated! Again we see two-way data binding.

All we did was update the property value in the controller and the corresponding value is already displayed in the DOM.

Note: All Angular directives use hump case (i.e. ngClick), and when used directly in HTML changes to ng-click. Often in JS we work with some kind of data sets that need to be looped through. For arrays, you used a for loop, looping through the array and storing the results you want in strings to output to the DOM later.

Angular has an ngRepeat directive to make it easier to loop through arrays. First of all, let’s create an array in the controller.

In an HTML template, you can simply connect the ngRepeat directive to the element whose content you want to loop through.

We connected the ngRepeat directive to the tr tag with the user in usersArray string. This means that the tr tag will be looped, and the user variable will be replaced with the value at the current iteration.

Our array is just a set of subarrays, and on the first iteration user [0] will display “BB”, user [1] will display “King” (ie at step zero).

Often in JS, you need to work with a collection of objects. Typically, data in this format is returned from databases or APIs. Let’s create a typical collection of objects.

Angular has a very convenient way to associate input data with property values, you can do this using the ngModel directive.

Let’s create a random string in our model, and create a function that will display this string via alert. In an HTML template, you can bind data from a form to a model, thereby opening a data binding connection.

Whenever the value of the input field changes, the value of the variable is automatically updated as well.

Calling alert in the function (using ngClick) will display the already updated value. We’ll end up with one of my favorite directives, ngClass, which allows you to dynamically assign classes to HTML tags.

You can read about different ways to use ngClass, but in our example we will get by with very simple code. Let’s set an empty class name and create a function that can change this value. Set the textClass value to the ng-class attribute. And also bind the changeTextClass function to the button.

When you click on the button, a function will be called that updates the property value and, accordingly, the class name. And just like that, our text turned pink, magic! 

Conclusion

Let’s summarize! In this article, we looked at the AngularJS examples, went through only the step-by-step basics of creating your project, but they may already interest you for further learning Angular. Angular is a beast and should be approached carefully. In the future, I hope to see you as a reader of the Angular article. So stay tuned!