ts-patterns — TypeScript patterns enforcer for Claude Code

Getting started

Install

# via gago-plugins marketplace
/plugin marketplace add gagoar/gago-plugins
/plugin install ts-patterns@gago-plugins
/reload-plugins

# standalone
/plugin marketplace add gagoar/typescript-patterns-enforcer
/plugin install ts-patterns@ts-patterns
/reload-plugins

What's included

/ts-patterns:check — inline skill, always active on .ts/.tsx files

ts-patterns:review — subagent, spawn for full reviews

/ts-patterns:checkAutomatically active while writing or editing TypeScript. Provides inline guidance on types, patterns, and anti-patterns without being invoked.
ts-patterns:reviewSpawn via the Agent tool for PR reviews, large refactors, or converting JavaScript to TypeScript. Runs as a dedicated subagent.

Reference

Principle	Rule
No 'any'	Use unknown and narrow, or define precise types
Explicit return types	Required on all public APIs
readonly by default	Use readonly unless mutation is required
async/await only	No callbacks or .then() chains
Typed errors	Custom error classes or discriminated-union results
Composition over inheritance	Prefer interfaces and composition

Reference

Anti-pattern	Preferred
`type Foo = any`	`type Foo = unknown` (then narrow)
`function f(): any`	`function f(): ConcreteType`
`.then(cb).catch(cb)`	async/await with try/catch
`class B extends A`	`interface I; class B implements I`
`try { } catch(e) { e.message }`	`catch(e) { if (e instanceof MyError) ... }`
`as SomeType`	satisfies or explicit narrowing