Instead of this:
// enforce lower/upper/alpha/numeric/special rules
for (rule in re) {
if
((pw.match(re[rule]) || []).length < o[rule])
return false;
}

I rewrote the code to this:

// enforce lower/upper/alpha/numeric/special rules
for (rule in re) {
if
((((pw.match(re[rule]) || []).length > 0) && (o[rule] == -1)) ||
((pw.match(re[rule]) || []).length < o[rule]))
return false;
}

And it worked!
Now, if I want to prohibit some characters, e.g. special characters, I just call the function with the option

special: -1
And I can do the same for numeric, uppercase, lowercase and alpha

I think maybe, the code could be modified, so that default value of any option (i.e. when the rule does not apply) could be -1 and if numeric/special characters are not allowed at all, then the value is 0 (or vice-versa 0=default, -1=not allowed)