If it's a popular issue, lots of people had the same issue, many will be nice enough to add their edge cases and make the answer better, most will not. Same goes for contributing to a package.
With a package you would be able to update when someone adds an edge case, but it might break your existent code and that edge case may be something that is not particular to your system.
If you don't want to get too deep in the issue, you can copy paste from SO, just the same you can just add a package.
If you want to understand the problem, you can read the answers, comments, etc. With the package you rely on reading code, I don't know how well those small packages are documented but I wouldn't count on it.
The only arguments that stands are code reuse and testability. But code reuse at the cost of the complexity the dependencies add, which IMO is not worth the time it'll take you to copy and paste some code from SO. Testability is cool but with an endless spiral of dependencies that quite often use one or more of the different (task|package|build) (managers|tools) that the node ecosystem has, I find it hard to justify adding a dependency for something trivial.