Final Keyword in Dart Programming

Final keyword in Dart

In Darts“final” means single-assignment, Once assigned with value then variable value can’t be changed. Final key word makes variable to hold constant value at compile time and runt time as well.

final int age = 25;
final var date = DateTime.now() // Final keyword accepts runt time data as well

Class Level Final Variables: The below example illustrates final keyword behaviour:

Class Product {
    final String productName;
    final int productId;
    Product(this.productName,this.productId);
}
void main() {
    Product pr= new Product("Laptop",101);
}

Class Level Static Variables:

Class Level static variables must be initialized at same time, does not allow at constructor level.

Class Product {
       final static productName = "Laptop";
  }

In summary:

• Variable values can not be changed once assigned with value
• Final keyword variables access compile time and run time initialization
• Class level static final variables must be initialized then and there
• Class level final variables can be initialized at same line or at constructor