Create Single Page Application Using AngularJS

AngularJS is a JavaScript framework. It is a library written in JavaScript. It contains HTML template language. It is an open-source structure that uses MVC JavaScript. It helps developers to maintain web infrastructure easily. AngularJS offers a collection of ready-made modules to simplify building single-page applications.

Why Do Businesses Need SPA?

Businesses are looking to transition from web applications to mobile applications. Single-page applications constantly interact with their end-users. They do not refresh the page but rather dynamically rewrite the current page. Gmail, Facebook, and Instagram are some of the most prominent examples of such apps.

These apps have fast loading times as they load faster than traditional web applications. The simple development process is also a huge plus point because it will be more cost-efficient than a complex application. They use the same code for both web and native apps. This same code makes the whole development process quicker. Since they need to load the page only once, they use less bandwidth than traditional apps.

How to develop a single-page application using AngularJs?

Setup AngularJS inside your project:

You can install this package either with npm or with Bower.

npm

npm install angular

Then add a to your index.html:

<script src="/node_modules/angular/angular.js">script>
<script src="/node_modules/angular/angular-route.js">script>

bower

bower install angular

Then add a to your index.html:

<script src="/bower_components/angular/angular.js">script>
<script src="/bower_components/angular/angular-route.js">script>

Or CDN

1. Need to add the angularJs library and angularJs route library inside the head tag.
   a. https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js
   b. https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular-route.js
2. If you learn AngularJS, first you will learn the basics like AngularJS Custom directives, expressions, filters, modules, and controllers.

Steps to develop a single-page app using AngularJS 

1. Need a html template.
   a. I use a bootstrap HTML template:
   i. https://startbootstrap.com/template-overviews/agency/
2. Define route.
   a. Home, About, services, portfolio, team, clients, contact
   b. Add Attributes href="#!yourRouteName"
3. Divided page content based on route.
   a. Example: About route content
   i. About.html
   ii. About page content display page content.
4. The ng-app directive defines the application, and the ng-controller directive defines the controller.
5. Write AngularJS code inside a js file.
6. Create a js file app.js
   a. Inside this file you define your app.
   b. var app = angular.module("myApp", ["ngRoute"]);
   c. Inside this file you define route.
   i. Declare route https://www.w3schools.com/angular/angular_routing.asp
7. Create another js file appCtrl.js
   a. Inside the appCtrl file you declare all controllers. You can create multiple files based on the controller.
   b. Create a controller and create an object:

   app.controller("aboutCtrl", function ($scope) );

8. Add attribute index.html page Inside html tag ng-app="myApp"
9. You show every page database on the controller.
   a. Example: about.html
   b. About page Controller: aboutCtrl
10. As you know, we have an about.html page. I use aboutCtrl inside the about.html page. The controller attribute uses the ng-controller directive and uses it to the top of the page.

Display data:

Display data using the about.html page. I used the ng-repeat directive.

<ul class="timeline">
 <li ng-repeat="aboutInfo in aboutInfos" ng-class-even="'timeline-inverted'">
   <div class="timeline-image">
                  <img class="img-circle img-responsive" 
            src="img/" alt="">
                div>
                <div class="timeline-panel">
                 <div class="timeline-heading">
                  <h4>h4>
                  <h4 class="subheading">h4>
                 div>
                 <div class="timeline-body">
                   <p class="text-muted">p>
                 div>
               div>
            li>
            <li class="timeline-inverted">
                <div class="timeline-image">
                  <h4>Be Part
                    <br>Of Our
                    <br>Story!h4>
                div>
             li>
           ul>

Key Characteristics of SPAs

Smooth User Experience: SPAs do not refresh pages so it offers a much smoother user experience.

Quick Loading: SPAs load only necessary data which lessens the bandwidth and server load.  

Client-side Routing: To make the app faster, SPAs use Client-Side Routing to manage navigation. 

API Driven: SPAs use APIs to fetch and send data. They do this to enable efficient interactions with the server.

Benefits of Single Page Application Development

Single-Page-Applications can be very beneficial for businesses. Especially for small companies who offer specialized services. 

Here is a list of Benefits of Single-Page-Applications: 

Refresh-Free Page: SPAs do not need to refresh because they dynamically update info by using JavaScript within the browser. It increases page responsiveness greatly.   

Easy Information Display: In these applications, you need to utilize the space with concise and particular words. This makes it easier for your clients to find information that you are trying to pass to them.  

Easier Debugging: Debugging is easier in SPAs in Chrome. The majority of the application logic is run on the client-side in the browser which makes it easier for developers to debug. They can just use Dev Tools to inspect and manipulate data if problems occur. 

Easy Navigation: These applications contain only one page which makes it very easy to navigate. Users will not get lost looking for information within the app. 

Challenges of SPAs

SEO Challenges: Since SPAs load data all at once in the server and it work on JavaScript, the URL does not change. Different pages do not have a unique URL. This makes it hard for search engines to index the SPA compared to traditional websites. 

Initial Load Time and Memory Consumption: If you have a slow internet connection, downloading all the HTML, CSS, and JavaScript code may take a lot of time. They sometimes also consume a lot of memory which can cause severe performance issues.

Best Practices for Single-Page Apps Development

Performance Optimization

By optimizing performance, you can reduce page load time. Often your performance can be hampered by framework-related scripts. If you optimize your AngularJS SPA perfectly then you can easily reduce these delays. 

SEO Optimization

You need to optimize your app with SEO. It is important for both user experience and visibility. Include human-readable keywords in URLs and make them descriptive. You can implement HTML5 mode in AngularJS and remove the hash (#) from your URL and create a cleaner and more SEO-friendly URL. 

Optimize UI/UX 

You can ensure user satisfaction with an optimized UI/UX design. Add animations for a smooth page transition. You can also use responsive designs for better user interactions. Dark mode is also a huge aspect of satisfying your users. 

Testing, Debugging, & Monitoring 

You can use different tools for end-to-end testing such as Playwright or Cypress. Testing, Debugging, and Monitoring is compulsory for the wellbeing of your SPA. You can also monitor application errors using logging tools like Sentry or LogRocket.  

Test in Different Devices

For a great user experience, you need to test your application on different devices. This way, you can ensure that all your users across different platforms and devices are enjoying the best service possible.

If you want to learn AngularJS the following links are useful:
https://www.w3schools.com/angular/
https://docs.angularjs.org/api/

Contributor:  Mamun Or Rashid, Nascenia