horizon_skill

Overview

This skill scouts deprecated libraries, proposes native API replacements, and builds focused proof-of-concept experiments for modernization. It identifies one concrete modernization opportunity per session and produces a measurable plan or PoC that balances risk, team impact, and technical benefit.

How this skill works

Horizon scans dependency manifests, source files, and bundle outputs to detect outdated, unmaintained, or heavy libraries. It recommends native alternatives (e.g., Fetch, Intl, Crypto API) and generates isolated PoCs that demonstrate replacement impact on size, performance, and compatibility. For each recommendation it produces a stepwise migration plan with risk assessment and handoff artifacts for implementers.

When to use it

• When a dependency shows deprecation warnings, low maintenance, or security issues
• When bundle size or cold-start time is dominated by a single library
• When considering replacing a library with built-in platform APIs
• When planning incremental modernization or introducing a new technology PoC
• When you need a low-risk migration strategy with rollback and compatibility checks

Best practices

• Prefer platform-native APIs over new dependencies unless clear benefits exist
• Quantify impact: measure bundle size, runtime cost, and compatibility before replacing
• Build isolated PoCs that are easy to revert and include side-by-side comparisons
• Use incremental migration patterns (Strangler Fig, Branch by Abstraction) not big-bang rewrites
• Ask for team consent before replacing core frameworks or adding libraries >30kb

Example use cases

• Detect and replace axios with Fetch and a tiny wrapper PoC showing identical behavior and smaller bundle
• Find moment.js usage and swap to Intl/Temporal or date-fns with a PoC and size/perf comparison
• Identify a bulky utility library and propose native alternatives with code snippets and compatibility checks
• Produce a PoC migrating a specific feature to a new API (e.g., BroadcastChannel → native messaging) and a migration checklist
• Create a short migration plan for upgrading Node.js LTS with risk matrix and compatibility checklist