Comment by smjburton
17 hours ago
While interesting and possibly helpful to new coders, are these quirks of the language still relevant when most development in Javascript is done using a framework (React, Vue, etc) these days? How often do these "gotchas" factor into "modern" Javascript development, especially in production? These type of articles seem to critique mechanics of the language that don't come up as often in practice.
The issue with variables and loops that OP described is worse with React, since you create closure inside the render function for event handlers, and if that closure captures any state variables (rather than a getter function for example), then you'll end up referencing stale state. React relies on linters to protect against this, but that only goes so far and the API design makes it easy to screw up, so you have to be on your toes.
Edit: To be clear, this is specifically a React hooks problem, not the old React with classes.
That's a fair point. Adding that to the original post would help provide context about why some of these quirks are still relevant to consider even when using a framework. I believe the assumption is often that frameworks abstract the Javascript "weirdness" away.
Quirks in this article and others like it are not something that would be encountered under normal circumstances unless the programmer is doing something silly (like skipping semicolons, ever touching eval, or relying on type conversions). Now, second point about loops (actually scopes and value declaration) is a core part of the language and needs to be learned, framework or no framework.
You are right, these quirks are not something you struggle with very often. The only one that has been troublesome at some point during my now 8 years as a professional, mainly Javascript with Vue, web developer is the automatic semicolon insertion example.
The simplest fixes for it is to just insert semicolons yourself, always use const, and not start any lines with [ or (.
It's worse in a framework, in the framework you need to know the oddities of the language as well as how the framework manages them.