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

Installation

npm install ts-toolbelt --save

yarn add ts-toolbelt

import * as T from 'ts-toolbelt'

// Do basic number operations
type test0 = T.N.Minus<'5', '20'> // -15

type O = {
    a: {
        b: {
            c: 'hello'
            d: 'goodbye'
        }
    }
}

// Deeply change a type
type test1 = T.O.P.Update<O, ['a', 'b', 'c' | 'd'], [1, 2, 3]>

// Or just merge them
type test2 = T.O.Merge<O, {x: 'hello'}>

And so much more... But before you start reading the docs:

The library is organized around TypeScript concepts:

• T.A: Any types
• T.B: Boolean types
• T.C: Class types
• T.F: Funtion types
• T.I: Iteration types
• T.N: Number types
• T.O: Object types
• T.S: String types
• T.T: Tuple types
• T.U: Union types

type test3 = T.A.Is<'hello', string>    // true

type test4 = T.T.Concat<[1, 2], [3, 4]> // [1, 2, 3, 4]

Documentation