Cascade Notation (..)

🎯 Mục tiêu: Chain operations trên cùng object.

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💡 Cú pháp

var button = Button()
  ..text = "Click me"
  ..color = Colors.blue
  ..onClick = handleClick;

// Tương đương
var button = Button();
button.text = "Click me";
button.color = Colors.blue;
button.onClick = handleClick;

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📝 Với method calls

var list = <int>[]
  ..add(1)
  ..add(2)
  ..add(3)
  ..shuffle();

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🔧 Null-aware cascade (?..)`

Button? button;
button
  ?..text = "Click"
  ..color = Colors.red;

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📱 Trong Flutter

final controller = TextEditingController()
  ..text = "Initial"
  ..selection = TextSelection.collapsed(offset: 0)
  ..addListener(() => print("Changed"));

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✅ Checklist

• .. returns the object, not the result
• Useful for builders/initialization
• ?.. for nullable objects

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