JavaScript as a first programming language? Some pros and cons

Recently I was working with a group of JavaScript developers in Australia. One of them observed (from maintaining code written by other developers) that he felt people coded in JavaScript in various styles, depending on their programming background, and that this stylistic mashup was perhaps a consequence of the fact that no-one used JavaScript as their first programming language, so they brought their stylistic baggage with them from a range of other ‘first’ languages.

Now I don’t know if there is actually no-one out there who first learned to program with JavaScript, but I suspect there would be very few, for good reason. Historically, JavaScript has been hard to write (no decent development environments), hard to debug, hard to test, and the browser runtimes were slow and flaky. That is no longer the case. IDEs like WebStorm make it easy to develop code, and when it is used with the plugin for Chrome, it also provides a full debugging environment. There are now a range of test tools available, including QUnit, and the quality of JavaScript engines in browsers has increased hugely.

So, would JavaScript be a good first programming language? It has some nice features that would make it seem attractive. It supports higher order functions that can be passed around using variables, it supports variadic functions for variable length parameter lists, and supports closures. You could teach people to use functions without the object oriented baggage of something like Java. Once you do want to use objects, its type system does not support all the features of a classical inheritance based language, but on the other hand it is dynamic, so complex data types can be reconstructed at run time, a really cool feature.

What about the down sides? Well there are still a few. The loose type system is a trap for the unwary, as is the lack of block scoping in favour of function scoping (though the ‘let’ keyword will address this once the major browsers all support it), and another danger is the ease with which global variables can be created (either deliberately or accidentally.) Whacky features like hoisting (where you can use a variable before you declare it) might also confuse the beginner, and running your code in a browser might get in the way of focusing on the basics of the language at the expense of being distracted by the UI.

Some of these issues might be addressed with tools like Microsoft’s TypeScript language, which brings type checking to JavaScript, and tedious browser document navigation and UI issues are simplified by libraries such as jQuery.

So, would I want to try teaching JavaScript as a first language? It probably depends on the type of class. For students at the ‘softer’/applied end of computing, learning the pre-eminent language of the Web, with quick and easy routes to seeing something useful happening in a browser, might not be such a bad place to start.