## [0.28.3](https://www.npmjs.com/package/@sinclair/typebox/v/0.28.3)

## Overview

Revision 0.28.3 adds a new Rest type to support variadic type composition.

## Contents

- Enhancements
  - [Variadic Types](#Variadic-Types)

<a href="Variadic-Types"></a>

## Variadic Types

Revision 0.28.3 adds a new type named `Type.Rest`. This type is used to extract a tuple array of type of `[...TSchema]`. The return value of this type is not strictly JSON Schema, however the tuple array can be used as a parameter to other types that accept tuples as their arguments.

### Tuple Concatenation

```typescript
// TypeScript

type A = [1, 2]

type B = [3, 4]

type C = [...A, ...B]

// TypeBox

const A = Type.Tuple([Type.Literal(1), Type.Literal(2)])

const B = Type.Tuple([Type.Literal(3), Type.Literal(4)])

const C = Type.Tuple([...Type.Rest(A), ...Type.Rest(B)])
```

### Tuple To Parameter

```typescript
// TypeScript

type P = [number, number]

type F1 = (param: [...P]) => void

type F2 = (param: [...P, number]) => void

// TypeBox

const P = Type.Tuple([Type.Number(), Type.Number()])

const F1 = Type.Function(Type.Rest(P), Type.Void())

const F2 = Type.Function([...Type.Rest(P), Type.Number()], Type.Void())
```