AngularJS and Angular 2 Comparison: What’s The Difference?

The front-end web development industry is full of various tools that are built to help you create an impeccable user interface. It is understandably difficult to choose just one for development as there are so many of them. AngularJS and Angular 2 are one of the most prominent front-end development tools that are often compared.

Considering that these two, AngularJS and Angular 2, bear a similar name, it is easy to confuse them. Besides, both of them are created for front-end development, and this causes even more confusion.

In order to help you make everything clear once and for all, we have prepared a detailed comparison between AngularJS and Angular 2. Keep reading to find out what these two are, what their pros and cons are, how they differ from each other, and under which circumstances each of them should be used.

AngularJS & Angular 2: Definitions

Let’s start with the basics to make sure that we are on the same page.

AngularJS was released in 2010. Originally developed by Google, it is a JavaScript framework that is currently open-source. As we have mentioned above, its purpose is front-end development. Its aim is to make developing single-page websites easier and resolve challenges that usually come with it. This framework uses HTML as the template language and extends its attributes with data binding and directives. All in all, AngularJS has proven to allow writing code that is readable and quick to develop.

As for Angular 2, right now it is used as an umbrella term for all the versions of Angular that were released after AngularJS. Today, these versions include Angular 2, 4, 5, and 6. Angular 7 is supposed to be released in September or October 2018. Angular 2 was developed by the team that had developed AngularJS and was supposed to be its complete rewrite. Just like AngularJS, Angular 2 is a platform for front-end web application development. It is open-source as well; however, it is based on TypeScript instead of JavaScript.

AngularJS Vs Angular 2 Pros And Cons

Nothing is perfect, nothing is without flaws. Just like any other development tool, both AngularJS and Angular 2 have their pros and cons. To help you figure out what they are, we prepared a comprehensive overview of the main pros and cons that you should be aware of.

AngularJS: Pros

  • Two-Way Data Binding

Data binding is made a lot easier with AngularJS: it is not necessary for developers to intervene manually at all. Two-way data binding means that any change that is made to the model is displayed in the view instantly and vice versa. Besides, two-way data binding allows easier DOM manipulation without the developers’ active participation

  • Directives

Introducing directives is what keeps any code organized, readable and easy to manage. With AngularJS, you can use directives for scripts and HTML pages. What is more important, the ability to use directives allows assigning special behaviors to the DOM.

  • Easy-To-Test

Testing and debugging can be done in a hassle-free way with AngularJS. The code written with the help of AngularJS is suitable for easy unit and end-to-end tests. Therefore, you can build a high-quality web application with no bugs and errors.

AngularJS: Cons

  • Low Performance

Even though AngularJS is often promoted as a good choice for building complex web applications, as experience shows, such dynamic web apps show low performance and lags due to the size. Additional tasks (such as DOM manipulation) can slow the web app down significantly. It is especially the case for if the user opens the web app on older rather than modern devices.

  • Difficult To Start Using

AngularJS is a tool that is rich with different options for fulfilling different tasks. So, there is a huge variety of options to choose from, and it can be quite confusing for some developers that are still novices in AngularJS. You need to spend quite a lot of time to become a pro in using AngularJS, and sometimes spending so much time is not an option for project development.

Angular 2: Pros

  • High Performance

The two main factors that make the performance of Angular 2 apps higher are hierarchical dependency injection and supporting Angular Universal. Hierarchical dependency injection runs the components and their dependencies in parallel. As for Angular Universal, it is a service that provides you with an opportunity to make the app render on the server side instead of the client browser, thus making the page load faster.

  • Component-Based Architecture

In case of the component-based structure, all the user interface elements are considered to be separate components that are interdependent. Thanks to this structure, components are easy to reuse and maintain. Besides, unit testing is also a lot easier to perform, and the code itself is more readable.

  • Mobile-First Approach

The mobile-first approach was one of the cornerstones in the developers’ minds when they were building Angular 2. Therefore, Angular 2 allows building not only web apps but also apps for Android and iOS platforms, i.e. it allows cross-platform app development. Additionally, Angular 2 makes sharing code easier than ever.

Angular 2: Cons

  • Difficult To Start Using

Similar to AngularJS, Angular 2 is quite difficult to master quickly. First of all, developers that have never used it before have to learn TypeScript and RxJS library. Besides, they need to wrap their heads around such concepts as dependencies injection, components, modules, etc.

  • Complexity

Even though the component-based structure is considered to be a pro for Angular 2, sometimes it may cause complications because managing the components can be too difficult. For instance, you need five files for one component, and you also need to inject dependencies and declare lifecycle interfaces. Some say that using Angular 2 means doing repetitive stuff most of the time.

What Are The Main Differences Between AngularJS And Angular 2?

So, now we know what AngularJS and Angular 2 are praised and criticized for. However, it is not enough to be completely sure which factors you should pay attention to when you consider choosing one of them for front-end web development. So, to help you understand the difference between AngularJS and Angular 2, we prepared a comprehensive AngularJS vs Angular 2 comparison to highlight the differences in architecture, language used, code reuse, mobile support, etc.

Architecture

AngularJS is based on the MVC model. This means that the basic component of this architecture that manages the data and the rules is the model. The view displays output based on the data in the model. The controller gathers input, processes it and converts it into commands that are sent to the model and the view.

As we have mentioned above, Angular 2 is based on the concept of the component architecture where the basic UI element is represented by a component. Components replaced controllers from AngularJS, and directives became the replacement for $scope. To put it simply, any component is basically a directive with a template. Its main purpose is to handle the view and the logic of the page.

File Type, Language, Expression Syntax

AngularJS uses JavaScript, and Angular 2 is based on TypeScript developed by Microsoft. TypeScript has significant advantages over JavaScript, such as type checking, object-oriented features, code optimization based on the OOPS concept, etc.

In order to bind an image/property/event using AngularJS, you need to remember the required ng directive to use it. In Angular 2, all you need to use is () to bind an event and [] to bind a property.

Code Reuse

Thanks to the introduction of components in Angular 2 and a heavy focus on code reusability in the component structure, reusing code in the form of components is easy and hassle-free. Besides, due to component splitting features, code reusability got higher. $scope that is present in AngularJS was removed in Angular 2.

Mobile Support

This is one of the main AngularJS and Angular 2 differences. AngularJS doesn’t provide developers with mobile support. However, Angular 2 was built with the mobile-first approach in mind, so it provides huge opportunities for code sharing for the purpose of cross-platform front-end development for Android and iOS.

Routing

In order to configure routing in AngularJS, you need to use $routeprovider.when(). In Angular 2, you have to use @RouteConfig{(…)}.

Performance

This can easily be a decisive AngularJS vs Angular 2 difference for many developers. As we have mentioned above, low performance is one of the main cons AngularJS is criticized for. This is why when the original development team decided to start working on Angular 2, they dedicated a lot of efforts to solving this issue and improving the performance.

For instance, even though two-way binding makes the lives of developers easier, it makes the client browser process a lot of data which slows the page load down. Angular 2 optimized the whole process, and with the help of Angular Universal you can decrease the processing on the client side.

Angular 2 has improved performance due to a better structure and tree-based change detection algorithm. Besides, hierarchical dependency injection system contributes to boosting the performance as well. So, it is easier to create big and complex applications with Angular 2.

AngularJS & Angular 2: Which To Choose?

Taking into account all the pros, cons and differences, we can guide you through the process of deciding which one to choose for front-end development, AngularJS or Angular 2.

So, AngularJS is a good choice if:

  • you already have experienced JavaScript developers on your team (learning AngularJS would be a lot easier for them);
  • your goal is the front-end development for a small-scale web application;
  • you do not need mobile support.

As for Angular 2, it can be a perfect fit in case:

  • you are going to develop the front-end for a complex large-scale web application;
  • mobile support is necessary for you;
  • high performance is crucial.

Conclusion

Surely, it is completely up to you whether to choose AngularJS or Angular 2. However, we strongly recommend you to consider all the pros and cons of both AngularJS and Angular 2 and the differences between them in order to determine which ones are the most crucial ones. Both AngularJS and Angular 2 are continuously supported by Google and have large communities of dedicated contributors, so they are not going to disappear or become less popular anytime soon.