especially as a library maintainer, I would really love to be able to say, for example, "you have to pass an email address to this prop" or "you have to pass a US phone number"
I get very frustrated when I sign up for storefronts using an email with a `.dev` address and some wanker decides that I shouldn't be allowed to give them money because my email address doesn't end in `@gmail.com`.
Stop this. Regex is not the right tool for this job. If you're going to use the regex hammer at least use the full standards compliant one shown here: https://stackoverflow.com/a/201378
> The problem with regular expressions is that telling someone that their perfectly valid e-mail address is invalid (a false positive) because your regular expression can't handle it is just rude and impolite from the user's perspective. A state engine for the purpose can both validate and even correct e-mail addresses that would otherwise be considered invalid as it disassembles the e-mail address according to each RFC.
But also I would use a standards-compliant regex. I also hate it when people don't implement standards to spec.