🔧✨ Tiny helpers for TypeScript applications
Small, focused utilities you import one at a time.
- 🎯 High-quality module design
- ⚡ Lightweight sub-package exports
- 📦 Tree-shakeable ES modules
- ✅ Zero dependencies
npm install @peerigon/typescript-toolkit --saveAlso available on JSR.
Import only the utilities you need. Each one is exposed as its own subpath:
import { assert } from "@peerigon/typescript-toolkit/assert";| Module | Description | Docs |
|---|---|---|
api |
Define a typed JSON API client with an overridable hook pipeline | → |
api/rate-limit |
Rate-limited fetch for defineApi (pacing + Retry-After) |
→ |
api/result |
defineApiResult — like defineApi, but returns Result.Sync |
→ |
assert |
Assert a value is not null or undefined, with TypeScript narrowing |
→ |
concurrency/once |
Run an async function at most once (single-flight + cache) | → |
concurrency/once/result |
once with a synchronous Result snapshot |
→ |
concurrency/exactlyOnce |
Invoke an async function exactly once; second call throws | → |
concurrency/exactlyOnce/result |
exactlyOnce with a synchronous Result snapshot |
→ |
concurrency/mutex |
Serialize async tasks (concurrency 1) | → |
concurrency/rate-limit |
Pace async task starts (max per sliding interval) |
→ |
need |
Assert a value is not null or undefined and return it with a narrowed type |
→ |
no-null |
Convert between null and undefined in JSON-like values (runtime + types) |
→ |
dedupe |
Remove duplicate values from an array while preserving first-occurrence order | → |
emitter |
Minimal typed event emitter with payload objects per event | → |
enums |
Lightweight string-enum alternative for erasableSyntaxOnly TypeScript projects |
→ |
map-leaves |
Deeply map leaves in JSON-like values (mutates arrays/objects in place) | → |
match |
Exhaustive pattern matching with compile-time case checks, similar to switch |
→ |
metadata |
Typed metadata attached to objects via per-channel WeakMap stores | → |
namespace |
Hierarchical namespaces with exclusive member claims and dotted prefixes | → |
result |
Type-safe error handling with pending, success, and error states | → |
signals |
Push-based reactive state with explicit watchers and signal.from adapters |
→ |
sleep |
Promise-based delay with optional AbortSignal cancellation |
→ |
stable-stringify |
Deterministic stringify for JSON + Map/Set/BigInt/Symbol/Date/RegExp | → |
stable-stringify/json |
JSON-only deterministic JSON.stringify with sorted object keys |
→ |
unwrap |
Extract values from Result or nullable types, with optional fallback support |
→ |
