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


You can cherry-pick what you import

Documentation

Make sure two types are identical



Playground

A assertion function that typescript understands

Make sure your zod schema exactly matches a given type:

Playground

Make sure you never forget a case in a switch


Playground

Make TypeScript believe whatever you say without having to write const obj2 = obj as Bar.
The more powerfully is to be able to tell TypeScript that obj ist not of type Bar:

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 other utilities that cannot be just type helpers.

Documentation website

Installation

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

Import in deno:

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

Install elsewhere:

$ npm install --save tsafe