Hacker News Reader

Comment by fiddlerwoaroof | Hacker News Reader

I wish people would stop promoting the singleton pattern: in almost every case I’ve seen, singletons are unnecessary tech debt and solve a problem that’s better solved with some form of dependency injection (and I don’t mean the XML/YAML monstrosities various frameworks force on you but rather constructor arguments or factory functions)

View on HN

The site is not "promoting" the singleton pattern. In fact, there is a "Tradeoffs"[1] section that calls it an anti-pattern in JavaScript.

In spite of that, there are plenty of reasonable use cases for singletons in many languages, including JavaScript. For example, ES Modules are effectively singletons. If you import the same module in multiple places, it only gets evaluated once.

Let's not turn the singleton pattern into forbidden knowledge.

[1]: https://www.patterns.dev/vanilla/singleton-pattern/#tradeoff...

Why pose DI as replacing singletons when they're used together all the time? Injecting dependencies to create a singleton repository or service class, which is shared across requests.

Singletons are globals and should be treated the same as every other global (that is, used sparingly and with care).

Worse is that singletons enfurece a single instance which is almost always unnecessary. It’s trivial to only create as many instances as you need.

Off the top of my head, rails (currentattributes), Laravel (facades) especially, and most iOS apps use singletons quite well. It’s all in moderation and depends highly on how it’s used, much like every other design pattern.

I think people just don’t like Singletons because they’ve been especially misused in the past but I guarantee the same argument stands for any other design pattern.

Yes, I have to admit my interest was piqued by the banner, and I then scrolled down, saw the first example was singletons, and closed the tab.

Reply on news.ycombinator.com