modern-javascript-patterns
This skill provides comprehensive guidance on ES6+ JavaScript features including async/await, destructuring, spread operators, arrow functions, and functional programming patterns. Use it when refactoring legacy JavaScript code, implementing modern syntax patterns, optimizing performance, or building maintainable applications that require contemporary language conventions and best practices.
git clone --depth 1 https://github.com/wshobson/agents /tmp/modern-javascript-patterns && cp -r /tmp/modern-javascript-patterns/plugins/javascript-typescript/skills/modern-javascript-patterns ~/.claude/skills/modern-javascript-patternsSKILL.md
# Modern JavaScript Patterns Comprehensive guide for mastering modern JavaScript (ES6+) features, functional programming patterns, and best practices for writing clean, maintainable, and performant code. ## When to Use This Skill - Refactoring legacy JavaScript to modern syntax - Implementing functional programming patterns - Optimizing JavaScript performance - Writing maintainable and readable code - Working with asynchronous operations - Building modern web applications - Migrating from callbacks to Promises/async-await - Implementing data transformation pipelines ## Detailed patterns and worked examples Detailed pattern documentation lives in `references/details.md`. Read that file when the navigation tier above is insufficient. ## Best Practices 1. **Use const by default**: Only use let when reassignment is needed 2. **Prefer arrow functions**: Especially for callbacks 3. **Use template literals**: Instead of string concatenation 4. **Destructure objects and arrays**: For cleaner code 5. **Use async/await**: Instead of Promise chains 6. **Avoid mutating data**: Use spread operator and array methods 7. **Use optional chaining**: Prevent "Cannot read property of undefined" 8. **Use nullish coalescing**: For default values 9. **Prefer array methods**: Over traditional loops 10. **Use modules**: For better code organization 11. **Write pure functions**: Easier to test and reason about 12. **Use meaningful variable names**: Self-documenting code 13. **Keep functions small**: Single responsibility principle 14. **Handle errors properly**: Use try/catch with async/await 15. **Use strict mode**: `'use strict'` for better error catching For common pitfalls (this binding, promise anti-patterns, memory leaks), see [references/advanced-patterns.md](references/advanced-patterns.md).
Test web applications with screen readers including VoiceOver, NVDA, and JAWS. Use when validating screen reader compatibility, debugging accessibility issues, or ensuring assistive technology support.
Conduct WCAG 2.2 accessibility audits with automated testing, manual verification, and remediation guidance. Use when auditing websites for accessibility, fixing WCAG violations, or implementing accessible design patterns.
Coordinate parallel code reviews across multiple quality dimensions with finding deduplication, severity calibration, and consolidated reporting. Use this skill when organizing multi-reviewer code reviews, calibrating finding severity, or consolidating review results.
Debug complex issues using competing hypotheses with parallel investigation, evidence collection, and root cause arbitration. Use this skill when debugging bugs with multiple potential causes, performing root cause analysis, or organizing parallel investigation workflows.
Coordinate parallel feature development with file ownership strategies, conflict avoidance rules, and integration patterns for multi-agent implementation. Use this skill when decomposing a large feature into independent work streams, when two or more agents need to implement different layers of the same system simultaneously, when establishing file ownership to prevent merge conflicts in a shared codebase, when designing interface contracts so parallel implementers can build against each other's APIs before they are ready, or when deciding whether to use vertical slices versus horizontal layers for a full-stack feature.
Decompose complex tasks, design dependency graphs, and coordinate multi-agent work with proper task descriptions and workload balancing. Use this skill when breaking down work for agent teams, managing task dependencies, or monitoring team progress.
Structured messaging protocols for agent team communication including message type selection, plan approval, shutdown procedures, and anti-patterns to avoid. Use this skill when establishing communication norms for a newly spawned team, when deciding whether to send a direct message or a broadcast, when a team-lead needs to review and approve an implementer's plan before work begins, when orchestrating a graceful team shutdown after all tasks are complete, or when debugging why teammates are not coordinating correctly at integration points.
Design optimal agent team compositions with sizing heuristics, preset configurations, and agent type selection. Use this skill when deciding how many agents to spawn for a task, when choosing between a review team versus a feature team versus a debug team, when selecting the correct subagent_type for each role to ensure agents have the tools they need, when configuring display modes (tmux, iTerm2, in-process) for a CI or local environment, or when building a custom team composition for a non-standard workflow such as a migration or security audit.