Chapter 6. Advanced Topics and Pitfalls in JavaScript

JavaScript has been called the "assembly language of the web". The analogy (it isn't perfect, but which analogy is?) draws from the fact that JavaScipt is often a target for compilation, namely from Clojure and CoffeeScript, but also from many other sources such as pyjamas (python to JS) and Google Web Kit (Java to JS).

But the analogy also references the foolish idea that JavaScript is as expressive and low-level as x86 assembly. Perhaps this notion stems from the fact that JavaScript has been bashed for its design flaws and oversights ever since it was first shipped with Netscape back in 1995. It was developed and released in a hurry, before it could be fully developed. And because of that, some questionable design choices made its way into JavaScript, the language that soon became the de-facto scripting language of the web. Semicolons were a big mistake. So were its ambiguous methods for defining functions. Is it var foo = function(); or function foo();?

Functional programming is an excellent way to side-step some of these mistakes. By focusing on the fact that JavaScript is truly a functional language, it becomes clear that, in the preceding example about the different ways to declare a function, it's best to declare functions as variables. And that semicolons are mostly just syntactic sugar to make JavaScript appear more C-like.

But always remember the language you are working with. JavaScript, like any other language, has its pitfalls. And, when programming in a style that often skirts the bleeding edge of what's possible, those minor stumbles can become non-recoverable gotchas. Some of these gotchas include:

However, these issues can be overcome with a little attention.