When is the best time to apply this optimization?

This optimization is most effective when you are performing repeated lookups against a static or semi-static collection, particularly inside loops or array methods like .filter().

Does this skill support TypeScript?

Yes, it is designed to work with both JavaScript and TypeScript, maintaining type integrity while refactoring collection types.

Why should I use a Set instead of an Array for lookups?

Sets provide O(1) average time complexity for membership checks, whereas Arrays require O(n) time, making Sets significantly faster as the collection size grows.

Will this refactoring change my application's logic?

No, the skill preserves the original logical intent of checking for existence; it only changes the underlying data structure to improve execution speed.

JS Performance Optimizer: Set & Map Lookups

Name: JS Performance Optimizer: Set & Map Lookups
Author: TheOrcDev

byTheOrcDev

•

1,535

Developer Tools

Optimizes JavaScript collection lookups by converting arrays to Sets and Maps for O(1) time complexity.

About

This skill enhances Claude's ability to identify and refactor inefficient membership checks within JavaScript and TypeScript codebases. By recognizing patterns where Array.includes() is used for repeated lookups, it suggests and implements high-performance alternatives using native Set or Map objects. This is particularly valuable when handling large datasets, filtering collections against allowlists, or optimizing performance-critical code paths where O(n) operations can lead to noticeable lag or overhead.

Key Features

Supports both JavaScript and TypeScript syntax and type safety
Optimizes data filtering and membership validation patterns
Automatically refactors arrays to Set or Map for constant-time lookups
Improves runtime performance for data-heavy applications
1,535 GitHub stars
Identifies inefficient Array.includes() calls in loops and filters

Use Cases

Improving processing speed in backend data transformation scripts
Optimizing validation logic that checks inputs against a static set of allowed values
Refactoring filter operations that check items against a large list of IDs

About

Key Features

Supports both JavaScript and TypeScript syntax and type safety
Optimizes data filtering and membership validation patterns
Automatically refactors arrays to Set or Map for constant-time lookups
Improves runtime performance for data-heavy applications
1,535 GitHub stars
Identifies inefficient Array.includes() calls in loops and filters

Use Cases

Improving processing speed in backend data transformation scripts
Optimizing validation logic that checks inputs against a static set of allowed values
Refactoring filter operations that check items against a large list of IDs