No one wants to see results for the letter "a", no one wants their database processing that search, and updating the UI while you're typing can be really distracting.
Don't make assumptions about what the user may or may not want to search for.
E.g. in my music collection I have albums from both !!! [1] and Ø [2]. I've encountered software that "helpfully" prevented me from searching for these artists, because the developers thought that surely noone would search for such terms.
No, you should definitely exercise good judgement in delivering a good UI to the user that doesn't lock up if they happen to type very quickly. But it is context dependent, and sometimes you will want to show them results for "a", sure. "No one" was rhetorical.
In your example, the developers have exercised poor judgment by making a brittle assumption about the data. That's bad. But there is no UX without some model of the user. Making assumptions about user's rate of perception is much safer (in a web app context, it would be a different story in a competitive esports game).
Edit: It does. So, this would be yet another of the squillion-ish examples to support the advice "Please, for the love of god, always enclose your URLs in '<>'.". (And if you're writing a general-purpose URL linkifier, PLEASE just assume that everything between those characters IS part of the URL, rather than assuming you know better than the user.)
I don't believe that they can, not unencoded. Check out the grammar in the relevant RFC[0], as well as the discussion about URL-unsafe characters in the RFC that's updated by 3986 [1], from which I'll quote below.
> Characters can be unsafe for a number of reasons. ... The characters "<" and ">" are unsafe because they are used as the delimiters around URLs in free text
Also note the "APPENDIX" section on page 22 of RFC1738, which provides recommendations for embedding URLs in other contexts (like, suchas, in an essay, email, or internet forum post.)
Do you have standards documents that disagree with these IETF ones?
If you're using the observed behavior of your browser's address bar as your proof that ">" is valid in a URL, do note that the URL
https://news.ycombinator.com/item?id=44826199>hello there
might appear to contain a space and the ">" character, but it is actually represented as
URLs with the characters ' ' and '>' in them are not valid URLs. Perhaps your web browser does things differently than my Firefox and Chrome instances, but when I copy out that pretty-printed URL from the address bar and paste it, I get the following string:
Yes. Unless you are pecking at your keyboard your eyes are free to look at the results on the screen and stop typing once you get the result you want. The only thing that's needed is for the results to be stable, i.e. if the top result for "abc" also matches "abcd" then it should also be the top result for "abcd". Unfortunately many search/autocomplete implementations fail at this but that's still a problem even with "debouncing".
It doesn't matter how fast you can read the results, you benefit from instant results as long as you can read them faster than you can complete typing.
Whatever delay you add before showing results doesn't get hidden by the display and user's reading latency, it adds to it.
"Instant," in the context of a user interface, is not zero seconds. It's more like 50ms to 1000ms (depending on the type of information being processed). If you want your user interface to feel snappy and responsive - then you don't want to process things as fast as the computer can, you want to process them in a way that feels instantaneous. If you get caught up processing every keystroke, the interface will feel sluggish.
I don't care if there are results for the letter "a", if they are instant.
Don't become unresponsive after one key to search for results. If the search impacts responsiveness, you need to have a hold-off time before kicking it off so that a longer prefix/infix can be gathered which will reduce the search space and improve its relevance.
