Exclusive

Since 1.0.0

Create mutually exclusive properties.

Signature

type Exclusive<T, K extends keyof T> = Omit<T, K> & {
  [P in K]: Pick<T, P> & Partial<Record<Exclude<K, P>, never>>
}[K]

Parameters

Parameter	Description
T	The base object type
K	The keys to make mutually exclusive

Description

Creates a type where specified properties are mutually exclusive - only one can be chosen. When one property is selected, other mutually exclusive properties must be never.

Examples

Basic Usage

import type { Exclusive } from 'uni-types'

type Button = Exclusive<{
  onClick: () => void
  href: string
  to: string
  disabled: boolean
}, 'onClick' | 'href' | 'to'>

// Valid: only onClick
const clickButton: Button = {
  onClick: () => console.log('clicked'),
  disabled: false
}

// Valid: only href
const linkButton: Button = {
  href: 'https://example.com',
  disabled: false
}

// Invalid: cannot have both onClick and href
const invalid: Button = {
  onClick: () => {},
  href: 'https://example.com', // Error: type is never
  disabled: false
}

Form Input Types

type Input = Exclusive<{
  type: 'text' | 'email' | 'password'
  options: string[]
  min: number
  max: number
}, 'type' | 'options'>

Related

• AtLeastOne - Require at least one property
• Merge - Merge two types