Async and Practical

Try/Catch

Fallback Value

try { ... } catch (e) { ... } runs the block and recovers when an exception is thrown.

Program

Play the program to safely divide by zero with a fallback.

exceptions.dart 
int safeDivide(int a, int b) {
  try {
    if (b == 0) throw FormatException('divide by zero');
    return a ~/ b;
  } catch (e) {
    return 0;
  }
}

void main() {
  print(safeDivide(10, 2));
  print(safeDivide(10, 0));
}
try/catch `catch (e)` binds the thrown value so the program can recover.
throw `throw FormatException(...)` raises an exception.
fallback Returning a default keeps the caller working.