2nd/10_Wiki/Topic_Programming/Frontend/Dart.md

---
id: wiki-2026-0508-dart
title: Dart
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [Dart language, dart-lang]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [dart, flutter, language, aot, jit]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: dart
  framework: flutter
---

# Dart

## 매 한 줄
> **"매 client-optimized language — JIT(dev) + AOT(prod) dual compile, sound null safety, isolate concurrency"**. 매 Google 의 Flutter 전용으로 설계 (2011→2018 pivot). 매 Dart 3.3+ (2024-2026) 의 records, patterns, sealed class 의 modern type system 도입.

## 매 핵심

### 매 dual compilation
- **JIT (development)**: 매 hot reload < 1s — Flutter dev 의 핵심.
- **AOT (production)**: 매 native machine code — startup 빠름, deterministic perf.
- **dart2js / dart2wasm**: 매 web target — Flutter Web 의 binary.

### 매 sound null safety (since 2.12)
- 매 `String?` (nullable) vs `String` (non-null) 의 compile-time 보장.
- 매 `late` keyword — 매 deferred init.
- 매 `!` (bang) — 매 명시적 unwrap.

### 매 Dart 3 의 modern features
- **Records**: `(int, String)` lightweight tuple.
- **Patterns**: destructuring + switch expression.
- **Sealed classes**: 매 exhaustive matching.
- **Class modifiers**: `final`, `interface`, `base`, `sealed`.

### 매 isolate concurrency
- 매 single-threaded event loop per isolate.
- 매 message-passing (no shared memory).
- 매 `Isolate.run()` (Dart 2.19+) 의 simple offload.

## 💻 패턴

### Null safety + late
```dart
class User {
  final String name;
  final String? nickname; // nullable
  late final int age;     // deferred init

  User(this.name, {this.nickname});

  void setAge(int a) => age = a;
}

final u = User('Yuna');
print(u.nickname?.toUpperCase() ?? 'NO NICK');
```

### Records (Dart 3)
```dart
(double, double) toPolar(double x, double y) =>
  (sqrt(x * x + y * y), atan2(y, x));

final (r, theta) = toPolar(3, 4);
print('r=$r, θ=$theta');

// Named record
({String name, int age}) profile = (name: 'Yuna', age: 28);
print(profile.name);
```

### Patterns + switch expression
```dart
sealed class Shape {}
class Circle extends Shape { final double r; Circle(this.r); }
class Square extends Shape { final double s; Square(this.s); }

double area(Shape sh) => switch (sh) {
  Circle(:final r) => 3.14159 * r * r,
  Square(:final s) => s * s,
};
```

### Async/await + Future
```dart
Future<User> fetchUser(int id) async {
  final res = await http.get(Uri.parse('https://api/u/$id'));
  if (res.statusCode != 200) throw Exception('fail');
  return User.fromJson(jsonDecode(res.body));
}

// Stream — 매 multiple async value
Stream<int> count(int n) async* {
  for (var i = 0; i < n; i++) {
    await Future.delayed(const Duration(seconds: 1));
    yield i;
  }
}
```

### Isolate (compute)
```dart
import 'dart:isolate';

Future<int> heavyCompute(List<int> data) =>
  Isolate.run(() => data.fold(0, (a, b) => a + b * b));

// 매 main isolate 의 block 없이 background work
final sum = await heavyCompute(List.generate(1_000_000, (i) => i));
```

### Extension methods
```dart
extension StringX on String {
  String get capitalized => isEmpty ? this : '${this[0].toUpperCase()}${substring(1)}';
}

print('hello'.capitalized); // "Hello"
```

### Mixin
```dart
mixin Loggable {
  void log(String msg) => print('[${runtimeType}] $msg');
}

class Service with Loggable {
  void doWork() => log('working...');
}
```

## 매 결정 기준

| 상황 | Approach |
|---|---|
| 매 Flutter mobile/desktop app | Dart (의무) |
| 매 CLI tool (cross-platform) | Dart AOT compile |
| 매 backend (Aqueduct/Shelf) | 매 가능 — 매 ecosystem 작음 |
| 매 web (no Flutter) | 매 비추천 — TS/JS 우세 |

**기본값**: 매 Flutter context 에서만 Dart 의 사용 — 매 standalone 은 Go/Rust/TS 의 권장.

## 🔗 Graph
- 부모: [[Flutter]]
- 변형: [[Flutter_AOT_Compilation_Dart]] · [[Dart_FFI_Foreign_Function_Interface]]
- 응용: [[Flutter_Web_-_Desktop]] · [[Flutter_Impeller]]
- Adjacent: [[TypeScript_Type_Safety]] · [[Cross-platform_Mobile_Development_Frameworks]]

## 🤖 LLM 활용
**언제**: 매 Flutter widget tree 작성, 매 isolate 기반 background work, 매 records/patterns 활용 의 modern Dart.
**언제 X**: 매 Flutter 외부 — 매 다른 ecosystem 에서 Dart 의 사용 의 의미 X.

## ❌ 안티패턴
- **매 dynamic 의 남용**: 매 type system 의 우회 — 매 sound null safety 의 무력화.
- **매 sync await chain**: 매 Future.wait 의 미사용 — 매 serialized 대기.
- **매 isolate 와 closure**: 매 capture-by-reference 의 함정 (sendable 만 가능).
- **매 print debug**: 매 debugPrint / logger 의 권장.

## 🧪 검증 / 중복
- Verified (dart.dev language tour, Dart 3.3 release 2024, Flutter 3.27).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — Dart 3 records/patterns/sealed 정리 |