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defineProp ​

Stability: experimental ⚠️ Experimental feature, use at your risk

Declare single prop one by one using defineProp.

FeaturesSupported
Vue 3✅
Nuxt 3✅
Vue 2✅
TypeScript / Volar✅

WARNING

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

Configuration ​

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

Volar ​

Require Volar >= 1.3.12

jsonc
// tsconfig.json
{
  // ...
  "vueCompilerOptions": {
    // "kevinEdition" | "johnsonEdition" | false
    "experimentalDefinePropProposal": "kevinEdition"
  }
}

Kevin's Edition (Default) ​

API Reference ​

ts
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>
// Declare prop with options
const count = defineProp('count', {
  type: Number,
  required: true,
  default: 0,
  validator: (value) => 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
//    ^? type: number | undefined

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

Johnson's Edition ​

API Reference ​

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

TypeScript ​

vue
<script setup lang="ts">
const count = defineProp<number>()
count.value
//    ^? type: number | undefined

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