you-are-not
Runtime type-checking written in TypeScript -- Not is a minimal, blazing fast, intuitive, API-centric, and customisable API payload sanitiser/type-checking/validation/error handing and messaging helper -- all in a small and neat pack.
functional-try
Error handling wrapper for cleaner use of strict type checking in TypeScript
es6-error
Easily-extendable error for use with ES6 classes