isDivisibleBy function
Returns true if the numeric value of str is divisible by n.
Both str and n are parsed as double; returns false on parse failure
or when n is zero.
Implementation
bool isDivisibleBy(String str, String n) {
try {
final divisor = double.parse(n);
if (divisor == 0) return false;
return double.parse(str) % divisor == 0;
} catch (_) {
return false;
}
}