Dart Pattern Matching

---
name: dart-use-pattern-matching
description: Use switch expressions and pattern matching where appropriate
metadata:
  model: models/gemini-3.1-pro-preview
  last_modified: Fri, 24 Apr 2026 15:08:55 GMT
---
# Implementing Dart Patterns

## Contents
- [Pattern Selection Strategy](#pattern-selection-strategy)
- [Switch Statements vs. Expressions](#switch-statements-vs-expressions)
- [Core Pattern Implementations](#core-pattern-implementations)
- [Workflows](#workflows)
- [Examples](#examples)

## Pattern Selection Strategy

Apply specific pattern types based on the data structure and desired outcome. Follow these conditional guidelines:

*   **If validating and extracting from deserialized data (e.g., JSON):** Use Map and List patterns to simultaneously check structure and destructure key-value pairs.
*   **If handling multiple return values:** Use Record patterns to destructure fields directly into local variables.
*   **If executing type-specific behavior (Algebraic Data Types):** Use Object patterns combined with `sealed` classes to ensure exhaustiveness.
*   **If matching numeric ranges or conditions:** Use Relational (`>=`, `<=`) and Logical-and (`&&`) patterns.
*   **If multiple cases share logic:** Use Logical-or (`||`) patterns to share a single case body or guard clause.