Skip to main content
Using Deno in production at your company? Earn free Deno merch.
Give us feedback

A collection of utilities to take your TypeScript development up a notch


(you can cherrypick what you import)

Documentation

Three GIFs to convince you that you need tsafe in your life


Assert things you know are true, get runtime errors where you were wrong:

Implement compile time unit testing

Playground

Make TypeScript believe whatever you say:

Motivations

Powerful TypeScript features like assertion functions or user-defined type guards are only useful if paired with utility functions.

TypeScript, however, only exports type helpers (e.g. Record, ReturnType, etc.).

This module provides «the missing builtins» such as the assert function and corrects frustrating aspects of default utility types such as ReturnType.

Documentation website

Installation

tsafe is both an NPM and a Deno module. (Achieved with denoify)

Import in deno:

import { assert, typeGuard, ... } from "https://deno.land/x/tsafe/mod.ts";

Install elsewhere:

$ npm install --save tsafe
#OR
$ yarn add tsafe