It is almost impossible to create a full-fledged software product using only one technology. This usually involves complete tech stacks – Standard combinations of tools and programming languages. As all software products consist of the client side and a server, there are usually two separate stacks that cover each of the layers. However, there are approaches that can be used to build web or mobile application from A to Z. These are called full stack development.

Accordingly, a generalist that has broad skills across all aspects of product engineering is usually called a full stack developer. 

Being considered unicorns due to their rare expertise and versatility, they are in high demand for large companies and startups alike, from Facebook and eBay to Munchery, Betterment or Tinder.

As an idea of a person equally proficient at HTML/CSS, Python, and SQL has become more of a myth, the approach towards acquiring new skills and learning quickly has led to the appearance of specialists strong in one particular stack. Let’s see what the most popular stacks are and how they’re used.

When talking about full stack JavaScript the first thing that comes to mind is the MEAN stack. It is a technology bundle that includes MongoDB, Express, AngularJS, and Node.js.

However, with the rapid growth of this approach, more alternative options for full stack JavaScript development are added. While server-side JavaScript programming with Node.js and Express web framework is the most common technology choice, other Node.js-based tools, such as Meteor, Sails.js, Koa, restify or Keystone.js, might be used as well.

The choice of possible frameworks for the front-end JavaScript is even greater. Aside from traditional AngularJS or AngularJS 2.0 frameworks, numerous libraries, such as React, Vue.js, Knockout.js, or Backbone.js, are typically used, depending on the project specifics.

As for the database, almost any MongoDB alternative can be used: MySQL, PostgreSQL, Apache CouchDB or Apache Cassandra.

The Pros of Full Stack JavaScript Development

The fact that companies like Groupon, Airbnb, Netflix, Medium and PayPal adopted the full stack JavaScript approach to build some of their products speaks for itself. However, small start-ups seem to enjoy using it as well. This is mostly due to the number of benefits full stack programming offers.

Common language, better team efficiency with less resources

Having all parts of your web application written in JavaScript allows for better understanding of the source code within the team. Therefore, there is no such thing as a gap between front and back end engineering that occurs when two teams are working separately using different technologies. Moreover, you can now work with only one team instead of two, for back and front end, which should significantly reduce the cost and effort of finding and retaining the right talent. Such a cross-functional team is a great asset when following Agile methodologies.

(*) Extensive code reuse

With full stack JavaScript, you save time through code reuse and sharing. Following the “don’t repeat yourself” (DRY) principle, you might be able to reduce the effort by reusing the parts of the code (or sharing libraries, templates, and models) on both back and front end that are very close in terms of logic and implementation. In other words, you don’t need to think about the Java-script utility equivalents in Python or Ruby, you just use the same utility on the server and in the browser. Reducing the number of lines of code by up to 40 percent is also a valuable capability when refactoring and maintaining the source code.

(*) High performance and speed

Node.js uses event-driven, non-blocking IO model that makes it lightweight and fast as compared to other commonly used back end technologies. To prove this, PayPal published a comprehensive report on the results they have seen in the process of migrating from Java to full stack JavaScript. The company was able to make the development almost 2 times faster while reducing the engineering personnel involved. Moreover, they have seen a dramatic improvement in performance, doubling the number of requests completed per second and decreasing the average response time by 35 percent for the same page. This means that the pages are served 200ms faster, which is definitely a noteworthy result.

(*) Extensive knowledge base

Backed by giants like Facebook and Google, JavaScript has a powerful and fast-growing community. Based on the Stack Overflow survey from 2016 quoted above, the language tops the list of the most popular technologies on the website with 62,588 votes. The website currently lists 1,543,025 questions tagged “JavaScript”, which indicates the high activity of the developer community and the huge amount of valuable information that can be found there.

(*) Free & open source toolset

Most of the full stack JavaScript development tools are free or open source projects. This means you don’t need to bear additional expenses for costly licenses or subscriptions. The tools that are open sourced are updated regularly and evolving fast due to the active community contributions. Instead of relying on a fixed set of technologies, you may use any of more than 475,000 tools (which have doubled since last year), hosted by the npm, the largest JavaScript modules registry in the world.

The Cons of Full Stack JavaScript Approach

Yet, no technology is perfect. Despite all the benefits the full stack approach offers, there is always some drawbacks to be aware of.

(*) Insufficiency with computation-heavy back end

When it comes to heavy computation and data processing on the server side, Node.js is not the best option. There are lots of far better technologies to handle projects like machine learning, algorithms, or heavy mathematical calculations. Having a single CPU core and only one thread, that processes one request at a time, it might be easily blocked by a single computationally intensive task. While the thread is busy processing the numbers, your application won’t be able to work with other requests, which might result in serious delays. Yet, there are numerous ways to overcome this limitation. By simply creating child processes or breaking complex tasks into smaller independent microservices, that use more suitable technologies and communicate with your back end, you can handle complex computational tasks in Node.js.

Relatively young technologies

When compared with PHP or Java, server-side JavaScript has been around for a shorter period of time. This results in a smaller knowledge base and limited integration capabilities. As an example, some developers cite the immaturity of the connections between Node.js and relational database tools, such as MySQL, Microsoft SQL Server, and PostgreSQL.

(*) Jack of all trades, master of none?

It is a common belief that a developer can truly master only one area of knowledge. With every other skill gained the quality of his/her expertise will decline. While syntax and grammar of JavaScript are mostly the same on client and server side, there are still many details to consider. Aside from being proficient in front end development, full stack JavaScript developers need to have an expertise in back end programming, such as HTTP protocol, asynchronous I/O, data storage fundamentals, cookies, etc. That is why some say that there are really no full stack engineers: Every one of them is either front or back end oriented. However, we have all the reasons to disagree, based on our own experience and strong JavaScript skills.

Drawbacks of every separate tool in the stack combined

As every technology stack, MEAN combines the weak sides of all 4 its elements. Most of them are minor technical limitations, which appear under certain circumstance. However, in order to use the stack, it’s important to realize possible bottlenecks of every tool and adjust your development strategy accordingly.