JS does have features for editing the history, but it's a trade-off of not polluting the history too much while still letting the user navigate back and forth
Both approaches (appending/rewriting) have their uses, the tricky part is using the right thing for the right action, fuck up either and the experience is abysmal.
Then a developer gets the task to create this, and they too don't push back on what exact URIs are being used, nor how the history is being treated. Either they don't have time, don't have the power to send back tasks to product, simply don't care or just don't think of it. They happily carry along creating whatever URIs make sense to them.
No one is responsible for URLs, no one considers that part of UX and design, so no one ends up thinking about it, people implement things as they feel is right, without having a full overview over how things are supposed to fit together.
Anyways, that's just based on my experience, I'm sure there are other holes in the process that also exacerbates the issue.
That said, I've also worked with some developers that didn't like intruding on their turf, so to speak. Though I've also worked with others that were more than happy to collaborate and very proactive about these sorts of things.
Furthermore, as a UX designer this is the sort of topic that we're unlikely to be able to meaningfully discuss with PMs and other stakeholders as it's completely non-visual and often trying to bring this up with them and discuss it ends up feeling like pulling teeth and them wondering why we're even spending time on it. So usually it just ended up being a discussion between me and the developers with no PM oversight.
I've had people be surprised by the request because its something they don't usually consider, but I've never had anyone actually push back on it.
Interacting with the URL from JS within the page load cycle is inherently complex.
For what it's worth, I'd also argue that the right behavior here is to replace.
But that of course also means that now the URL on the history stack for this particular view will always have the filter in it (as opposed to an initial visit without having touched anything).
Of course the author's case is the good/special one where they already visited the site with a filter in the URL.
But when you might be interested in using the view/page with multiple queries/filters/paramerers, it might also be unexpected: for example, developers not having a dedicated search results page and instead updating the query parameters of the current URL.
Also, from the history APIs perspective, path and query parameters are interchangeable as long as the origin matches, but user expectations (and server behavior) might assign them different roles.
Still, we're commenting on a site where the main view parameter (item ID, including submission pages) is a query parameter. So this distinction is pretty arbitrary.
And the most extreme case of misusing pushState (instead if replace) are sites where each keystroke in some typeahead filter creates a new history entry.
All of this doesn't even touch the basic requirement that is most important and addressed in the article: being able to refresh the page without losing state and being able to bookmark things.
Manually implementing stuff like this on top of a basic routing functionality (which should use pushState) in an SPA is complex very quickly.
I would have one state for when the user first entered the page, and then the first time they modify a filter, add a 2nd state. From thereon, keep updating/replacing that state.
This way if the user clicks into the page, and modifies a dozen things they can
1. Refresh and keep all their filters, or share with a friend 2. Press back to basically clear all their filters (get back to the initial state of the page) 3. Only 1 more press of back to get back to where-ever they came from
Unless of course, you initially visited the page with a stateful URL.