Annoyingly, npm audit relies on github's advisory DB, which is currently incorrectly flagging all versions of these packages, not just the compromised ones.
What do you mean irritatingly? Do you mean that you think 'grep -r "_0x112fa8"' is not enough or are you irritated that npm audit is flagging as if it was compromised?
I'm irritated because I expected to find at least one compromised file, but there were none. It may be, though, that we only use the affected packages as transitive development dependencies, in which case they are not installed locally. But a sliver of doubt remains that I missed something.
[0]: https://gist.github.com/martypitt/0d50c350aa7f0fc73354754343...