tsafe

What is tsafe?

The tsafe package provides utility functions for TypeScript that help ensure type safety and improve type inference. It includes functions for exhaustive type checks, type assertions, and more.

What are tsafe's main functionalities?

exhaustiveSwitch

The exhaustiveSwitch function is used to ensure that all possible cases in a switch statement are handled. If a case is not handled, it throws an error, helping developers catch missing cases at compile time.

function exhaustiveSwitch(value: never): never { throw new Error(`Unhandled case: ${value}`); }

assert

The assert function is used to assert that a condition is true. If the condition is false, it throws an error. This is useful for runtime checks that also inform TypeScript's type system.

function assert(condition: any, msg?: string): asserts condition { if (!condition) { throw new Error(msg); } }

Other packages similar to tsafe

ts-essentials

The ts-essentials package provides a set of essential utilities for TypeScript, including advanced types and type guards. It offers more comprehensive utilities compared to tsafe, focusing on enhancing TypeScript's type system capabilities.

type-fest

Type-fest is a collection of essential TypeScript types. It provides a wide range of utility types that extend TypeScript's built-in types, offering more flexibility and power. While tsafe focuses on runtime type safety, type-fest is more about enhancing type definitions.

README

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