<h1 id="heading-sealed-class">Sealed Class</h1>
<ul>
<li>To create a known, enumerable set of subtypes, use the sealed modifier. This allows you to create a switch over those subtypes that is statically ensured.
</li>
<li>The sealed modifier prevents a class from bring extended or implemented outside its own library. Sealed classes are implicitly abstract.
</li>
<li>They cannot be constructed themselves.
</li>
<li>They can have factory constructors.
</li>
<li>They can define constructors for their subclasses to use.
</li>
</ul>
<pre><code class="lang-dart">sealed class Result{}

class Success extends Result {
 final String message;
 Success(this.message);
}

class Error extends Result {
 final String errorMessage;
 Error(this.errorMessage);
}

void main() {
 final result1 = Success('Operation successfull');
 final result2 = Success('Operation failed');

 handleResult(result1);
 handleResult(result2); 

}

void handleResult(Result result) {
 if(result is Success) {
 print('Success : ${result.message}');

 } else if (result is Error){
 print('Error : ${result.errorMessage}');
 }
}
</code></pre>
<pre><code class="lang-dart">Success : Operation Successfull
Error : Operation Failed

Exited.
</code></pre>

# Sealed Class

* To create a known, enumerable set of subtypes, use the sealed modifier. This  
    allows you to create a switch over those subtypes that is statically ensured.
    
* The sealed modifier prevents a class from bring extended or implemented  
    outside its own library. Sealed classes are implicitly abstract.
    
* They cannot be constructed themselves.
    
* They can have factory constructors.
    
* They can define constructors for their subclasses to use.
    

```dart
sealed class Result{}

class Success extends Result {
    final String message;
    Success(this.message);
}

class Error extends Result {
    final String errorMessage;
    Error(this.errorMessage);
}

void main() {
    final result1 = Success('Operation successfull');
    final result2 = Success('Operation failed');

    handleResult(result1);
    handleResult(result2);    

}

void handleResult(Result result) {
    if(result is Success) {
        print('Success : ${result.message}');

    } else if (result is Error){
        print('Error : ${result.errorMessage}');
    }
}

```

```dart
Success : Operation Successfull
Error : Operation Failed

Exited.
```

Dart : Sealed Class

Sealed Class