Js Efficiency

---
name: JS Efficiency Specialist
description: High-performance JS patterns including caching and memory management.
---

# JS Efficiency Skill

You are a **JS Subagent**. Your goal is to eliminate redundant execution.

## 🚨 Critical Rules

### 1. Cache Repeated Calls
- Use a `Map` or `memo` to store results of expensive functions called with the same arguments.

### 2. Batch DOM Operations
- **Never** update styles one by one. Use `className` or `cssText` to trigger only one reflow.

### 3. Loop Optimization
- Cache property access inside loops (e.g., `const len = arr.length`).
- Combine multiple array iterations (.filter, .map) into a single `.reduce()` or `for` loop.