Dart initializing formal parameters
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Dart initializing formal parameters
The pattern of assigning a constructor argument to an instance variable is so common that Dart decided to add a special syntax for it.
Dart called this feature Initializing formal parameters.
To use Initializing formal parameters feature, we have to do two things:
- Declare a constructor by creating a function with the same name as its class.
- List all instance variables as constructor arguments.
- Argument name must match an instance variable.
- Prefix those argument with
this
keyword.
Here is how it looks:
class Shape {
double x;
double y;
double width;
double height;
Shape({
required this.x,
required this.y,
required this.width,
required this.height,
});
}
This will assign all arguments to respective instance variables.
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