While it began (primarily) as a desktop-constrained browser-only language launched by Netscape in 1995, JavaScript has conquered virtually every internet-connected platform on Earth: phones, tablets, desktop, servers and thousands of devices in the Internet of Things—the works. JavaScript is everywhere.
As Pluralsight author Jonathan Mills puts it: “As a JavaScript developer, I can write code that runs anywhere, not just the web. Backend code with Node and Electron, desktop with Electron, and mobile with React native. That flexibility makes JavaScript skills incredibly valuable.”

Complexity drives JavaScript’s dominance

The complexity of JavaScript makes it harder to learn, and harder to use effectively, which has created a lot of demand for knowledge around it. On Pluralsight.com, the viewing data we see indicates continued demand for learning JavaScript—roughly 3X more than other Pluralsight content is viewed.
JavaScript is broad, including front-end development, command-line interface (CLI) applications, desktop (GUI) applications, mobile applications, back-end development and combinations of all the above.
Pluralsight Author Cory House explains, “Thanks to innovative projects like Node.js, Electron, and React Native, developers can write web apps, native mobile apps, web APIs, server-side processes, and even desktop apps using JavaScript. They say software is eating the world. For all these reasons, much of that software is written in JavaScript. It’s not just for the web anymore. ”

Dependencies keep demand high

In the past, more custom “vanilla” JavaScript code would be written to support each individual website, but these days being a JavaScript developer requires a mastery of a wide range of tools, libraries and frameworks.
In a recent job posting for a “Sr. Full-stack JavaScript Developer,” candidates were asked to have the following experience and knowledge: ECMAScript (the underlying JavaScript standard) 2015/2016 (ES6/7), JavaScript transpilers (Babel, TypeScript), and JavaScript build tools (WebPack, Browserify, Grunt, Gulp); Expertise in Node.js, NPM package ecosystem, and Node.js web frameworks such as Express.js, Hapi.js, Sails.js; Experience with modern JavaScript UI & web frameworks such as React, Angular, or Ember; Experience writing unit tests using Karma, Jasmine, Mocha, Protractor, Jest or other JavaScript testing frameworks.
This job post neatly illustrates one of two issues facing JavaScript today: the explosion of frameworks, libraries and tools has created brittle lists of dependencies and made it nearly impossible for developers to keep up. 
The other major issue for JavaScript is the language itself. Its combination of loose typing and semantics is the bane of many a developer’s existence. This has given rise to languages which transpile (or compile) to JavaScript. These languages, including TypeScript, Scala.js, Elm, and ClojureScript, help manage JavaScript and make it more reliable. But they’re yet another thing developers who want to have a competitive skillset have to know.

Keeping pace with JavaScript

JavaScript’s popularity is a signal of a mature and robust technology with numerous practitioners and an exceptionally diverse ecosystem, which can be deployed to solve problems across a wide array of platforms. Ironically, these tools may lead to JavaScript itself declining in popularity as more focus moves to those tools, frameworks, packages and languages which make JavaScript development productive, efficient and pleasant.
Statistics from JavaScript package manager NPM show that, on average, 561 new JavaScript packages are uploaded every single day. The next highest, Packagist, comes in at 139 per day, barely a fourth that of JavaScript. Not only does a developer need to keep up on the changes made to his or her chosen frameworks and libraries, but they also need to keep up with the latest developments in order to stay competitive in the job market.
While a developer’s current role may not require much proficiency in JavaScript, it’s no guarantee that a future desirable role will not. Given the dominance of this technology, developers must actively fight their own skill depreciation or risk being left behind as the JavaScript ecosystem continues its rapid evolution.

About the author:

Abe Burnett
As a data scientist at Pluralsight, Abe creates cutting-edge, transformative products and platforms including the Pluralsight Technology Index—a real-time view of in-demand software technologies. Abe adores working at the nexus of statistics, economics, development, communication and collaboration.