Apply Gang of Four and related design patterns in JavaScript and TypeScript. Use when implementing creational, structural, or behavioral patterns, or when the user mentions factories, builder, prototype, flyweight, singleton, object pool, adapter, wrapper, decorator, proxy, bridge, composite, facade, chain of responsibility, command, interpreter, iterator, mediator, memento, EventEmitter, EventTarget, state, strategy, template method, visitor, revealing constructor, actor, service locator, or any other pattern.
Prepare an npm package for publishing. Handles version bump, CHANGELOG update, typings check, test run, README refresh, package.json audit, and npm pack verification. Use when the user asks to prepare a release, bump version, publish a package, or do release prep.
Apply error handling and recovery patterns in JavaScript/TypeScript or Node.js. Use when implementing error handling, retry logic, or when the user mentions domain errors, error recovery, error escalation.
Apply Metarhia JavaScript style. Use when writing or editing .js, .mjs, .ts files (with certain corrections for typescript), formatting code, or when the user asks about code style or linting.
Implement and use data structures in JavaScript. Use when working with arrays, sets, maps, other collections, queues, lists, trees, graphs, circular buffers, caches, or when the user mentions data structures, BTree, or choosing between Map/Object/Set/Array.