TypeScript-first test assertion functions with precise type narrowing

ESLint rules for catching unhead misuse, type-narrowing issues, and v2-to-v3 migration problems.

Zero-dependency TypeScript runtime validation toolkit for composable type guards and natural type narrowing.

ESLint plugin for runtime reliability — enforces error handling, network timeouts, null checks, and safe type narrowing.

type narrowing for typescript

yaebal filters — composable, type-narrowing update filters (and/or/not) for ctx.filter().

✔ Document One of properties in OpenApi \ ✔ Scalable way to define polymorphic response without the need to change a shared file \ ✔ Easy type narrowing for consumers of OpenApi docs \ ✔ TypeScript Support – Fully typed for a smooth developer experience.

Framework-agnostic TypeScript utility functions — arrays, objects, strings, async control-flow, dates, numbers, browser file downloads, changelog/version parsing, and a couple of `Array` extensions with better type-narrowing.

Type safe utility for defining static constants with automatic type narrowing and additional helper functions

Composable runtime value checks that play well with TypeScript's type narrowing

A simple library for two-step type-narrowing

Simple utility for `if (typeof object[property]) ...` type narrowing.

TypeScript tiny narrowing helpers you better use.

TypeScript assertion and type-guard toolkit for runtime validation and type narrowing.

Types and related utilities for TypeScript

A comprehensive collection of strongly-typed predicate functions and type guards for TypeScript, providing runtime type checking and type narrowing capabilities.

Check if a value is a Fetch network error

A set of types, type checks, and type guards for simpler, safer, and easier to read code.

Type declarations for the Telegram API

Sanity CLI core package