dart-use-pattern-matching agent skill by flutter

At a glance

Before you install

Read from the skill's files at the directory's October 19, 2026 snapshot: what ships with it, what its code reads, and the terms it is published under.

• Bundled scripts: none.
• License: BSD-3-Clause, an open-source or open-content license.

Install dart-use-pattern-matching

The skills CLI works with Claude Code, Codex, Cursor and other agents; the other routes copy the folder by hand.

npx skills add https://github.com/flutter/skills/tree/main/skills/dart-use-pattern-matching

tmp="$(mktemp -d)"
git clone --depth 1 https://github.com/flutter/skills.git "$tmp/repo"
mkdir -p .claude/skills
cp -R "$tmp/repo/"skills/dart-use-pattern-matching .claude/skills/
rm -rf "$tmp"

python3 ~/.codex/skills/.system/skill-installer/scripts/install-skill-from-github.py \
    --repo flutter/skills \
    --path skills/dart-use-pattern-matching

flutter/skills is third-party code. Read SKILL.md and any bundled scripts before you install it.

How the author describes it

Applies Dart 3 pattern matching, switch expressions, and destructuring idiomatically to validate data schemas, handle algebraic data types, and decompose control flow. Use when refactoring complex if-else chains, parsing polymorphic JSON or API responses, destructuring Lists, URI/path segments, String.split() tokens, Records, or Maps, or enforcing exhaustiveness on sealed classes. Don't use for simple boolean conditions, single-variable type promotion (use `is`), or basic collection filtering.

From the description field of SKILL.md. Agents read this line to decide when to load the skill.

Sections in SKILL.md

• Contents
• Pattern Selection Strategy
• Switch Statements vs. Expressions
• Core Pattern Implementations
• Pragmatic Balance & Anti-Patterns
• 1. Prefer is Type Promotion over if-case for Single Promotable Variables
• 2. Consolidate Nullable Types in Switch Arms
• 3. Preserve Fast-Fail Validation (Do Not Silently Drop Data)
• 4. Avoid Single-Case or Boolean Switches
• 5. Avoid Gratuitous Object Destructuring
• 6. Avoid if-case for Standalone Scalar Comparisons
• Workflows
• Task Progress: Implementing Pattern Matching
• Feedback Loop 1: Exhaustiveness Checking (Static Verification)
• Feedback Loop 2: Runtime Map & JSON Pattern Verification
• Examples

Files in the skill folder

• SKILL.md
• examples/json_patterns.dart

Suede Skill Check: 81/100 · B

dart-use-pattern-matching passes the required frontmatter check and all seven graded checks, which cover the SKILL.md format, a declared license and a commit in the last year. Those checks earn 56 of the score’s points; the rest come from description quality, instruction depth, bundled files, maintenance and curated-list citations. How the score works.

Where this skill is cited

flutter/skills is listed from its publisher's official collection or a listing request.

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