orDefault

static assert(is(TypeFromOptional!OptionalJsonValue == JsonValue));
OptionalJsonValue someJson;
assert(someJson.orDefault == JsonValue.init);
someJson = JsonValue(5);
assert(someJson.orDefault == JsonValue(5));

static assert(is(TypeFromOptional!(Optional!int) == int));
Optional!int someInt;
assert(someInt.orDefault == 0);
someInt = 5;
assert(someInt.orDefault == 5);