extONLYALPHA function

dynamic extONLYALPHA(
  1. dynamic value
)

ONLYALPHA(str): keeps only English letters

Implementation

dynamic extONLYALPHA(dynamic value) => varToStr(value)
    .split("")
    .where((c) => RegExp(r"[A-Za-z]").hasMatch(c))
    .join();