[Flutter] How to explicit pass 'undefined' to a function, trying to fall back to default value?

Say I have a function named printInt.

void printInt({int v = 0}) {
print(v);
}


I read integer v from some JSON map object.

void main(){
...
int v = someJSONMap['v']; // i don't know whether v is null

// i want to do something like this:
// (which not valid in dart)
// printInt(v: v == null ? undefined : v);
}


I can not change printInt (not belongs to me), and I don't want to write codes like this cause the real situation is much more complex.

// i don't want to write like this:
if(v == null){
print();
}else{
print(v);
}


Is there any alternative solution for the above?

Continue reading...