10  Type

10.0.1 All Aboard the Type Test Express: is and is!

Buckle up, coding comrades! We’re about to embark on a thrilling journey aboard the Type Test Express, the one-stop solution to avoid the pitfalls of type confusion. Dart’s type test operators are like the friendly conductors checking tickets, making sure everyone (or in our case, every variable) is in the right place.

There are two conductors in our train analogy, is and is!, and they handle our passengers - variables - with care and precision.

• is The Identity Inspector: This operator, like an attentive conductor, checks if a variable is of a certain type. If it is, it responds with a courteous nod (returns true). But if it’s not, it shakes its head (returns false).

var aTrainTicket = 'Choo Choo!';
print(aTrainTicket is String); // True! This ticket is indeed a string.

is! The Non-Identity Inspector: This operator has an edgier approach. Instead of checking if a variable is of a certain type, it checks if it is not of a certain type. If the variable’s type does not match, it gives a triumphant thumbs-up (true). But if it does match, it frowns in disappointment (false).

print(aTrainTicket is! int); // True! Our ticket is no integer, it's a string!

These conductors, is and is!, are here to keep our code on track, making sure that all variables are precisely what we expect them to be. Just remember, when in doubt, give a shout out to is and is!.

So, as we pull into our next station, the Land of Control Flow, remember to keep your variables in check and your types in order!