Introduction:

Designing a front-end infrastructure is not easy when new Javascript frameworks are developing at extremely fast pace. With new frameworks coming in the market, and the trending new updates of the existing ones, let breakdown some of the benefits and limitations of the existing popular JS frameworks.

Angular

Angular is a known Typescript-based JavaScript MVVM framework, founded in 2009, backed by Google and used for developing highly interactive web applications. It is widely used by Google, Forbes, WhatsApp and many other Fortune 500 companies. Right from the beginning, AngularJS became extremely popular among engineers. A strong community provided enough training materials, discussions, and third-party tools to embark on using AngularJS as well as find a solution to nearly every arising issue, the trend also continues even today with Angular 2+.

Benefits:

• Component-based architecture that provides a higher quality of code: Components can be thought of as small pieces of an interface that are independent of each other.

• Reusability: Developers can reuse components across different parts of an application. This is particularly useful in enterprise-scope applications that use similar elements like search boxes, date pickers, sorting lists, etc.

• Readability: Encapsulation also ensures that new developers – who’ve been recently on-boarded to a project – can read code better and eventually reach their plateau of productivity faster.

• Unit-test friendly. The independent nature of components simplifies unit tests, quality assurance procedures aimed at verifying the performance of the smallest parts of the application, units.

• Maintainability: Components that are easily decoupled from each other can be easily replaced with better implementations.

• RxJS: RxJS is a library commonly used with Angular to handle asynchronous data calls. It allows for handling events independently in parallel and continuing execution without waiting for some event to happen and leaving a web page unresponsive. RxJS has a steep learning curve, but once you master it, it makes life easier. The library operates with Observables, sort of blueprints that describe how data streams are combined and how the application reacts to variables in these streams. Basically, once you’ve got a grip on observables, you can easily reuse them, manage, and combine them as Lego blocks reducing the complexity of such programming operations as building drag-and-drop features, handling large volumes of data in chunks, etc. You can leverage RxJS with other frameworks that function with front-end (React.JS) or back-end operations (Node.JS), but in Angular RxJS is a necessity, which we’ll also discuss in the cons section.

Limitations:

• Migrating legacy systems from AngularJS to Angular requires time: The difference between AngularJS and Angular is large, so is the path of migration from the past to the future. Unlike updating from say Angular 5 to Angular 6, it won’t be a breeze, especially if you’re dealing with a legacy monstrosity.There are different ways to do that, one of which is to use a hybrid approach. It entails having both old and new Angular operating at the same time while you incrementally update the whole product. Not only does it take time, you’ll have to review many tools, the transition to a new language, and deal with a heavier app.

• Steep learning curve
  On-boarding new developers familiar with JavaScript to learn and use new Angular, will be challenged compared to similar React or Vue on-boarding. The array of topics and aspects to be covered is large: modules, dependency injection, components, services, templates, etc. Another barrier is RxJS, a reactive programming library for asynchronous programming. Learning it, at least on the basic level, is mandatory for using Angular. Engineers complain about error messages that are too cryptic to grasp without additional research followed by trial-and-error manipulations.
  TypeScript, as we’ve already mentioned in the benefits section, is also a bone of contention. While TypeScript improves maintainability of code, having to learn it doesn’t make the curve gentler.

React

Maintained by Facebook, React is a JavaScript library for building UI components for web applications. It is widely used by Facebook(duh!), Uber, Netflix, Udemy and may more.

Benefits:

• Updates process is optimized and accelerated.
• JSX makes components/blocks code readable. It displays how components are plugged or combined with.
• React’s data binding establishes conditions for creation dynamic applications.
• Prompt rendering. Using comprises methods to minimize number of DOM operations helps to optimize updating process and accelerate it.
• Testable. React’s native tools are offered for testing, debugging code.
• SEO-friendly. React presents the first-load experience by server side rendering and connecting event-handlers on the side of the user:   1. React.renderComponentToString is called on the server. 2. React.renderComponent() is called on the client side. 3. React preserves markup rendered on the server side, attaches event handlers.  
• Up to date. Facebook team supports the library. Advice or code samples can be given by Facebook community.
• Using React+ES6/7, application gets high-tech and is suitable for high load systems.

Limitations:

• Learning curve. Being not full-featured framework it is requered in-depth knowledge for integration user interface free library into MVC framework.
• View-orientendness is one of the cons of ReactJS. It should be found 'Model' and 'Controller' to resolve 'View' problem.
• Not using isomorphic approach to exploit application leads to search engines indexing problems.
• Lots of developers dislike JSX React’s documentation, manuals are difficult for newcomers’ understanding.
• React’s large size library.

Vue

New in the market, Vue.js is one of the most-discussed and rapidly growing JavaScript framework. Released in February 2014, you can build interactive UIs using HTML, CSS and Javascript. It is widely used by Alibaba. Gitlab, and is being picked up by many developers globally.

Benefits:

• Documentation: Vue.js has incredibly well-thought documentation which is very thorough and well-written. All a beginner requires to write their first application is just some basic Javascript and HTML.

• Size: One of the most significant features I found with Vue is it’s size. The production ready build of Vue.js weighs only 18kb after gzipping, compared to approximately 80kb for minified jQuery (depending on what version you use) and 29kb after gzipping. It should also be noted that the Vue.js ecosystem is also small and fast.With Vue.js, users can separate the template-to-virtual-DOM compiler and even the run time.

• Scalability and versatility: It works well both as a library and a fully fledged framework. My next project will involve almost a pure Vue.js web application that consumes the Wordpress REST API. So it provides me with the speed of development I need whilst providing the less technical content creators in my company with the familiarity and ease they trust by bolting into a CMS like Wordpress.

• Readability for the perfectionist: I find Vue.js incredibly easy to read. Functions are incredibly accessible and if your naming conventions are right “thisFunctionWillDoThis” then you won’t go far wrong. For example, for form submissions I like to break each field validation into its own function. The times where the designers have requested I change full name to first and last name fields (or vice versa) it pays to have a separate functions.

• Easier to learn than $jQuery: This one is a little subjective, but I found it much, much easier to start building the basics with Vue.js over more traditional Javascript frameworks such as jQuery. It is incredibly approachable — the documentation is excellent, and although some have found issue with the community being mainly non-English speaking, I’ve found the community incredibly supportive.

Limitations

• Lack of some common solid plugins/components: Due to the relative age of Vue.js, there is a fairly well known lack of common plugins that make working with various tools easier. Google Maps being a pretty common example. I have yet to work with Google Maps within Vue.js, and always resort to vanilla Javascript.

• Evolving fast: A lot of Vue learners have mentioned that Vue.js is evolving rather fast, so a lot of the examples you find online may be outdated. I’d always invest in a solid online course, a good read of the documentation and a solid book to boot.

• Minor issues with iOS and Safari: I’ve found minor issues with older iOS and Safari devices; but, being entirely honest the issues are often fixable, albeit with a little more digging for some issues.

• Reactivity caveats: If you read the documentation, there are some reactivity caveats, like setting an item from an array directly (e.g., this.items[key]=value) or adding a new data property. This might be both good and bad depending on use cases. However, for most cases it's nice to have everything specified upfront inside data.

Conclusion:

Based on the comparisons listed above, which is the best JavaScript framework to go for? I think the choice of the framework depends on your preference, requirement, and the use-case. However, if you are developing a large app and looking for a very stable platform to support it, then you can go with Angular, provided you are very comfortable using Typescript. Also if you are looking for object-oriented-programming or have a huge team of developers, then Angular is highly recommended. If you don’t want to use Angular but want to develop huge apps, then React is your best bet. The platform not only is favorable for large teams but also has a massive ecosystem revolving around it. Finally, if you are willing to experiment with a very promising framework which is steadily growing and is easy to pick up, then Vue.js is your best choice. The application will have cleaner code and can be developed by a small team.