It is impossible on iOS
tag.is('mifareClassic') is therefore always false on iOS — not undefined, not
a method that throws when called, just a guard that does not match:
It is chipset-dependent on Android
MIFARE Classic is an optional Android technology. Devices with Broadcom or some Intel NFC controllers do not implement it, and on those devices the technology is simply absent from the tag’s tech list. The library gates on what the tag actually reports rather than guessing:No heuristics are used to decide this. The library being replaced probed
/dev/bcm2079x-i2c and
/dev/pn544, scanned /system/lib, and carried a hardcoded special case for one Lenovo model.
All of that is guesswork about a question the platform answers directly.