Which programming languages are attracting users at the fastest rate?

According to GitHub, the languages that are growing quickest are three relative newcomers: the Java replacement Kotlin, JavaScript spin-off TypeScript, and the configuration language HCL.

These languages have seen the largest growth in the proportion of contributors to code repositories over the past year, GitHub’s annual Octoverse report found.

Also shooting up the chart is Microsoft’s command-line shell and scripting language PowerShell and Mozilla’s Rust, which is designed to offer similar performance to C++, while adding fine control over memory management.

“We’re seeing trends toward more statically typed languages focused on thread safety and interoperability: Kotlin, TypeScript, and Rust are growing fast this year,” says the GitHub report.

Kotlin — 2.6x more contributors

Kotlin is a modern alternative to Java that is easy to learn and use.

The open-source, statically-typed language gained major traction last year when Google threw its weight behind Kotlin and announced it was an officially supported language for building Android apps.

Kotlin has been described by a Netflix senior software engineer as offering “some of the best features of other languages” combined with “interoperability with Java”, due to its ability to run on the Java virtual machine (JVM).

The language, created by JetBrains in 2011, shot up from number 46 to 27 in the RedMonk rankings in the back half of 2017 and was chosen as the second favorite language by developers in a Stack Overflow survey earlier this year.

Apart from Android apps, Kotlin is also used to build backend and server-side applications.

Earlier this month, Google and JetBrains announced they had established the Kotlin Foundation to oversee the development of the language.

HCL — 2.2x more contributors

A new name in the list is HCL (HashiCorp Configuration Language), a configuration language used for setting up programming environments, software libraries, and other application dependencies.

Commonly used by DevOps engineers, an advantage of HCL is that it is interoperable with JSON, a widely used language for configuring development environments, due to the HCL API being able to accept JSON as an input.

HCL was created by DevOps company HashiCorp as a more human-readable form of JSON and YAML, while also being less verbose than JSON.

“Our configuration language (HCL) is designed to be written and modified by humans,” HashiCorp writes on its HCL project page.

“Our goal with HCL is not to alienate other configuration languages. It is instead to provide HCL as a specialized language for our tools, and JSON as the interoperability layer.”

TypeScript — 1.9x more contributors

TypeScript is a superset of JavaScript, meaning it allows developers to write in vanilla JavaScript, but also adds new features to help them build larger and more complex programs.

SEE: Hiring kit: Python developer (Tech Pro Research)

Its useful additions to JavaScript include static types and other features that make it easier to work with classes and modules, alongside support for simpler tools for verifying and checking the structure of the code.

With a little bit of work, TypeScript can be used as a replacement for JavaScript. Because it compiles to JavaScript, it can typically be used wherever the developer normally uses JavaScript, whether that be for a web app running in the browser or backend code in a node.js environment.

Earlier this year, Kris Borchers, executive director of the JS Foundation, told TechRepublic that TypeScript is more of a complement to JavaScript than it is a replacement and that the popularity of both are growing side by side.

TypeScript 3.1 was released earlier this month, introducing mappable tuple and array types and version redirects.

The language’s popularity was also evident in its rise to number seven in the list of most commonly used languages used on GitHub, an improvement over last year when it entered the top 10 for the first time.

Top languages and other favorites

There were fewer surprises in the Octoverse report’s list of top languages, those whose code repositories had the greatest number of contributors, with the list dominated by the usual suspects and the versatile web and server-side scripting language JavaScript in pole position.

JavaScript also had a heavy influence on the list of most popular topics searched for, with the app framework React topping the list and backend environment node.js at number 3.

There continues to be a sharp growth in interest in what GitHub calls open-source projects, with the fastest-growing projects headed up by the documentation for Microsoft’s Azure cloud platform.

Meanwhile, the most popular open-source project by number of contributors is again a Microsoft offering, the IDE Visual Studio Code, followed by Facebook’s React native app framework and Google’s Tensorflow machine-learning framework.

The big takeaways for tech leaders:

  • GitHub found that Kotlin, HCL and TypeScript are the fastest-growing languages on the online code repository.
  • The site says there is a trend toward more statically typed languages focused on thread safety and interoperability.