Flutter × Dart 3 Complete Guide — Pattern Matching, Sealed Classes & Records

Dart 3 introduced Pattern Matching, Sealed Classes, and Records — features that fundamentally change how you write Flutter apps. More expressive, safer code with less boilerplate.

Dart 3 Key Features

Patterns — Destructure and match values

Sealed Classes — Exhaustive type checking

Records — Lightweight anonymous types

Class Modifiers ( final , interface , base , mixin )

Records — Lightweight Composite Types

Return multiple values without a dedicated class:

// Before: needed a Map or custom class // Dart 3: Records ( String name , int age ) getUser () = > ( 'Kanta' , 28 );

final ( name , age ) = getUser (); print ( ' $name ( $age )' ); // Kanta (28)

// Named fields ({ String title , double price , bool inStock }) getProduct () = > ( title: 'Premium Plan' , price: 9.99 , inStock: true );

print ( getProduct () .…