General best practices for Dart development. Covers code style, effective Dart, and language features.

Dart Best Practices 1. When to use this skill Use this skill when: Writing or reviewing Dart code. Looking for guidance on idiomatic Dart usage. When NOT to use (Abstention Guardrails) Do NOT apply this skill or refactor code when: Public API Breaking Changes : Refactoring would alter public API contracts, return types, or parameter signatures in published packages without a coordinated major SemVer bump. Dogmatic Micro Optimizations : Rewriting clear, readable code for negligible theoretical gains (e.g. replacing clear string concatenation in a simple one line log message with multiline quotes). Domain Specific or Code Generated Files : Generated files ( .g.dart , .freezed.dart , protobufs) or files where line lengths and string layouts are managed by code generators. Explicit Type Annotations in Public Interfaces : Replacing explicit type annotations with var or final where explicit types document the public API surface or disambiguate complex generics. 2. Best Practices Multi line Strings Prefer using multi line strings ( ''' ) over concatenating strings with + and \n , especially for large blocks of text like SQL queries, HTML, or PEM encoded keys. This improves readability and avoids lines longer than 80 chars lint errors by allowing natural line breaks. Avoid: Prefer: Line Length Avoid lines longer than 80 characters, even in Markdown files and comments. This ensures code is readable in split screen views and on smaller screens without horizontal scrolling. Prefer: Target 80 characters for wrapping text. Exceptions are allowed for long URLs or identifiers that cannot be broken. Discovery Multi line Strings To find candidates for multi line strings, search for string concatenation with + involving newlines: Regex : ['"]\s \+\s ['"] Regex : \+\s ['"]. \\n Line Length Rely on the lines longer than 80 chars lint from the analyzer. Related Skills [dart modern features] : For idiomatic usage of modern Dart features like Pattern Matching (useful for deep JSON extraction), Records, and Switch Expressions. [dart modern features]: https://github.com/kevmoo/dash skills/blob/main/skills/dart modern features/SKILL.md

dart-best-practices