defineProp

Stability: experimental ⚠️ Experimental feature, use at your risk

Declare single prop one by one using defineProp.

Features	Supported
Vue 3	✅
Nuxt 3	✅
Vue 2	✅
TypeScript / Volar	✅

WARNING

defineProp can not be used in the same file as type-declared defineProps.

Configuration

VueMacros({
  defineProp: {
    /**
     * 'kevinEdition' | 'johnsonEdition'
     * @default 'kevinEdition'
     */
    edition: 'kevinEdition',
  },
})

Kevin's Edition (Default)

API Reference

defineProp<T>(propName)
defineProp<T>(propName, options)

// propName parameter can be optional,
// and will be inferred from variable name
const propName = defineProp<T>()

Basic Usage

vue

<script setup>
// Declare prop
const count
 = defineProp
('count')

// Infer prop name from variable name
const value
 = defineProp
()

// access prop value
console
.log
(count
.value
)
</script>

With Options

vue

<script setup lang="ts">
// Declare prop with options
const count
 = defineProp
('count', {
  type
: Number
,
  required
: true,
  default
: 0,
  validator
: (value
: number) => value
 < 20,
})
</script>

TypeScript

vue

<script setup lang="ts">
// Declare prop of type number and infer prop name from variable name
const count
 = defineProp
<number>()
count
.value


// Declare prop of TS type boolean with default value
const disabled
 = defineProp
<boolean>('disabled', { default
: true })
disabled
.value

</script>

With Reactivity Transform

const foo = $defineProp<string>('foo')
//    ^? type: string | undefined

const bar = $(defineProp('bar', { default: 'bar' }))
//    ^? type: string

Johnson's Edition

API Reference

// the prop name will be inferred from variable name
const propName = defineProp<T>()
const propName = defineProp<T>(defaultValue)
const propName = defineProp<T>(defaultValue, required)
const propName = defineProp<T>(defaultValue, required, rest)

Basic Usage

vue

<script setup>
// declare prop `count` with default value `0`
const count
 = defineProp
(0)

// declare required prop `disabled`
const disabled
 = defineProp
(undefined
, true)

// access prop value
console
.log
(count
.value
, disabled
.value
)
</script>

With Options

vue

<script setup lang="ts">
// Declare prop with options
const count
 = defineProp
(0, false, {
  type
: Number
,
  validator
: (value
: number) => value
 < 20,
})
</script>

TypeScript

vue

<script setup lang="ts">
const count
 = defineProp
<number>()
count
.value


// Declare prop of TS type boolean with default value
const disabled
 = defineProp
<boolean>(true)
disabled
.value

</script>

With Reactivity Transform

vue

<script setup lang="ts">
const foo = $defineProp<number>()
//    ^? type: number | undefined

const bar = $(defineProp(0, true))
//    ^? type: number
</script>

Volar Configuration

tsconfig.json

jsonc

{
  "vueCompilerOptions": {
    "plugins": ["unplugin-vue-macros/volar"],
    "vueMacros": {
      "defineProp": true,
    },
    // "kevinEdition" | "johnsonEdition" | false
    "experimentalDefinePropProposal": "kevinEdition",
  },
}