dart-logic-patterns

name	dart-logic-patterns
description	Apply efficient algorithms, data structures, and Dart 3 pattern matching for clean business logic. Use when implementing search, sorting, debouncing, memoization, or exhaustive control flow in domain layers.
metadata	{"platforms":"dart","languages":"dart","category":"logic"}

Algorithms & Logic

The efficiency of your business logic directly impacts battery life and responsiveness.

Complexity Analysis

• Big O Awareness: Understand the cost of your operations. Avoid O(n²) or higher on the main thread for datasets larger than a few hundred items.
• Data Structure Selection:
  • Map: Fast key-based lookups.
  • Set: Fast unique item management.
  • List: Fast indexing and sequential access.
  • LinkedHashSet/Map: Preserves insertion order while providing fast lookups.

Logic Patterns

• Debouncing: Delay execution until a user stops interacting (e.g., search-as-you-type).
• Throttling: Limit execution to at most once every interval (e.g., scrolling events).
• Memoization: Cache the results of expensive pure functions based on their arguments. Use package:memoize or custom implementations.
• Pattern Matching (Dart 3+): Use switch expressions and exhaustive pattern matching for control flow instead of deeply nested if-else chains. This is a core part of clean Dart logic.

Search & Sort

• Binary Search: Use for sorted lists to transform O(n) searches into O(log n).
• Efficient Sorting: Use Dart's built-in list.sort(), which uses highly optimized algorithms. Provide targeted Comparable implementations for custom objects.

Business Logic Organization

• Pure Functions: Keep business logic in pure, testable functions outside of UI classes.
• Fail Fast: Use guard clauses to handle edge cases and invalid states early.
• Validation Logic: Keep complex validation in a separate domain layer, reusable across different screens.