Dart best practices

Dart Best Practices

Priority: P1 (OPERATIONAL)

Best practices for writing clean, maintainable Dart code.

• Scoping:
  • No global variables.
  • Private globals (if required) must start with _.
• Immutability: Use const > final > var.
• Config: Use --dart-define for secrets. Never hardcode API keys.
• Naming: Follow effective-dart (PascalCase classes, camelCase members).
• Strings: Prefer single quotes; use double quotes only for interpolation needs.
• Trailing Commas: Always use trailing commas for multi-line literals/params.
• Expression Bodies: Prefer => for single-expression functions/getters.
• Collections:
  • Use .map, .where, .fold, .any over manual loops when clarity improves.
  • Type empty collections (<String>[], <String, User>{}) to avoid dynamic.
  • Use collection if/for and spread operators for composable lists/maps.
• Async: Always await futures unless intentionally fire-and-forget.

import 'models/user.dart'; // Good
import 'package:app/models/user.dart'; // Avoid local absolute

Anti-Patterns

• ❌ var result = fetchOrders() — use final or an explicit type; var only for locally obvious types in short scopes
• ❌ import 'package:myapp/features/orders/order_model.dart' within the same package — use relative imports for intra-package files
• ❌ Top-level mutable List<Order> cachedOrders = [] — no global mutable state; use DI or encapsulate in a class
• ❌ list.forEach((item) => doSomething(item)) — prefer tear-offs: list.forEach(doSomething)