People are already scanning npm constantly. You can limit yourself to pre-scanned packages by setting npm's minimum release age setting to 1 or 2 days (a timeframe that all the recent high-profile malicious package versions were unpublished within).
Note to self: the test suite for vetting a package should include setting the system date some time in the future, to check if an exploit is trying to sleep long enough to defeat the age limit.
Note to self: the test suite for vetting a package should include setting the system date some time in the future, to check if an exploit is trying to sleep long enough to defeat the age limit.