ts-toolbelt

What is ts-toolbelt?

The ts-toolbelt package provides a comprehensive set of type utilities to improve TypeScript typing and enable type transformations, checks, and more complex operations. It enhances TypeScript's static typing capabilities and helps in building more robust type-safe applications.

What are ts-toolbelt's main functionalities?

Object Manipulation

Merge two types into one. This is useful for combining properties from multiple objects into a single type.

{ type Merged = Merge<{name: string}, {age: number}>; // Result: {name: string, age: number} }

Type Checking

Check if two types are equivalent. This utility helps in validating type structures for consistency.

{ type check = Equals<{a: string}, {a: string, b: number}>; // Result: false }

Conditional Types

Apply conditional logic to types. This feature allows for conditional type assignments based on certain conditions.

{ type Conditional = If<true, 'Yes', 'No'>; // Result: 'Yes' }

Other packages similar to ts-toolbelt

utility-types

Provides a collection of utility types for TypeScript, similar to ts-toolbelt. While utility-types focuses more on transformations and mappings, ts-toolbelt offers a broader range of type operations including type checks and advanced manipulations.

type-fest

A package that includes a variety of utility types for TypeScript. Type-fest is similar to ts-toolbelt but tends to be simpler and more focused on everyday use cases, whereas ts-toolbelt provides more comprehensive and complex utilities for advanced type manipulation.

README

TypeScript's largest utility library

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📖 Documentation · 📣 Announcements · 🐞 Report Bug · 🍩 Request Feature · 🤔 Ask Questions

About

ts-toolbelt is the largest, and most tested type library available right now, featuring +200 utilities. Our type collection packages some of the most advanced generic mapped types, conditional types, and recursive types on the market.

Spend less time, build stronger. Benefit from a wide range of generic type functions to achieve better type safety - easily.

We are just like lodash, or ramda, but applied to the type system. Our mission is to provide you with simple ways to generate, transform, and create types. We abstract all those complex type checks away for you. We provide a standard, reusable, and simple API to achieve greater things with TypeScript.

ts-toolbelt is a well organized package that can help you perform advanced operations on union types, object types, function types, and literal types. It is coherently designed for building robust, flexible, and type safe software.

We answer the question to "How can I do this in TypeScript?". We are a community. Everyone is welcome to come ask questions about types. We welcome beginners and advanced developers to come take part. Welcome!

Getting Started

Prerequisites

npm install typescript@^4.1.0 --save-dev

For best results, add this to your tsconfig.json

{
  "compilerOptions": {
    // highly recommended (required by few utilities)
    "strictNullChecks": true,

    // this is optional, but enable whenever possible
    "strict": true,

    // this is the lowest supported standard library
    "lib": ["es2015"],
  }
}

Installation

npm install ts-toolbelt --save

Hello World

import {Object} from "ts-toolbelt"
// Check the docs below for more

// Merge two `object` together
type merge = Object.Merge<{name: string}, {age?: number}>
// {name: string, age?: number}

// Make a field of an `object` optional
type optional = Object.Optional<{id: number, name: string}, "name"}>
// {id: number, name?: string}

You can level-up, and re-code this library from scratch.

Documentation ⤢

Imports

The project is organized around TypeScript's main concepts:

Any	Boolean	Class	Function	Iteration	List
Number	Object	Object.P	String	Union	Test

TIP How to choose categories? Match your type with them.

There are many ways to import the types into your project:

• Explicit

  import {Any, Boolean, Class, Function, Iteration, List, Number, Object, String, Union} from "ts-toolbelt"
  

• Compact

  import {A, B, C, F, I, L, N, O, S, U} from "ts-toolbelt"
  

• Portable

  import tb from "ts-toolbelt"
  

You can also import our non-official API from the community:

import {Community} from "ts-toolbelt"

TIP The community API is for our community to publish useful types that don't see fit in the standard API.

Archives ⤢

EXAMPLE https://millsp.github.io/ts-toolbelt/4.2.1/

Good to Know ⤢

In this wiki, you will find some extra resources for your learning, and understanding.

Are you missing something? Participate to the open-wiki by posting your questions.

Running tests

For this project

To run the lint & type tests, simply run:

npm test

For your project

Want to test your own types? Let's get started:

import {Number, Test} from "ts-toolbelt"

const {checks, check} = Test

checks([
    check<Number.Plus<"1", "30">, "31", Test.Pass>(),
    check<Number.Plus<"5", "-3">, "2",  Test.Pass>(),
])

TIP Place it in a file that won't be executed, it's just for TypeScript to test types.

Continuous Integration

The releases are done with Travis CI in stages & whenever a branch or PR is pushed:

• Tests are run with npm test
• Tests against DefinitelyTyped
• Releases to npm@[branch-name]

Compatibility

The project is maintained to adapt to the constant changes of TypeScript:

ts-toolbelt	typescript
9.x.x	^4.1.x

Major version numbers will upgrade whenever TypeScript had breaking changes.

Otherwise, the release versions will naturally follow the semantic versioning.

What's next

• Automated performance tests

  # performance is checked manually with 
  npx tsc --noEmit --extendedDiagnostics
  

• Need to write more examples

Related Projects

Name	Intro
eledoc	🌒 A material dark theme for TypeDoc
utility-types	Collection of utility types, complementing TypeScript built-in mapped types and aliases

License