covariant method
Assert that JavaScript's x
is the proper type represented by this
Type.
Implementation
@override
bool covariant(x) {
final min = BigInt.from(2).pow(_bits - 1) * BigInt.from(-1);
final max = BigInt.from(2).pow(_bits - 1) - BigInt.one;
if (x is BigInt) {
return x >= min && x <= max;
} else if (x is int) {
final v = BigInt.from(x);
return v >= min && v <= max;
} else {
return false;
}
}