Utility Types
INFO
This page only lists a few commonly used utility types that may need explanation for their usage. For a full list of exported types, consult the source code.
PropType<T>
Used to annotate a prop with more advanced types when using runtime props declarations.
Example
tsimport type { PropType } from 'vue' interface Book { title: string author: string year: number } export default { props: { book: { // provide more specific type to `Object` type: Object as PropType<Book>, required: true } } }
See also Guide - Typing Component Props
MaybeRef<T>
- Only supported in 3.3+
Alias for T | Ref<T>
. Useful for annotating arguments of Composables.
MaybeRefOrGetter<T>
- Only supported in 3.3+
Alias for T | Ref<T> | (() => T)
. Useful for annotating arguments of Composables.
ExtractPropTypes<T>
Extract prop types from a runtime props options object. The extracted types are internal facing - i.e. the resolved props received by the component. This means boolean props and props with default values are always defined, even if they are not required.
To extract public facing props, i.e. props that the parent is allowed to pass, use ExtractPublicPropTypes
.
Example
tsconst propsOptions = { foo: String, bar: Boolean, baz: { type: Number, required: true }, qux: { type: Number, default: 1 } } as const type Props = ExtractPropTypes<typeof propsOptions> // { // foo?: string, // bar: boolean, // baz: number, // qux: number // }
ExtractPublicPropTypes<T>
- Only supported in 3.3+
Extract prop types from a runtime props options object. The extracted types are public facing - i.e. the props that the parent is allowed to pass.
Example
tsconst propsOptions = { foo: String, bar: Boolean, baz: { type: Number, required: true }, qux: { type: Number, default: 1 } } as const type Props = ExtractPublicPropTypes<typeof propsOptions> // { // foo?: string, // bar?: boolean, // baz: number, // qux?: number // }
ComponentCustomProperties
Used to augment the component instance type to support custom global properties.
Example
tsimport axios from 'axios' declare module 'vue' { interface ComponentCustomProperties { $http: typeof axios $translate: (key: string) => string } }
TIP
Augmentations must be placed in a module
.ts
or.d.ts
file. See Type Augmentation Placement for more details.See also Guide - Augmenting Global Properties
ComponentCustomOptions
Used to augment the component options type to support custom options.
Example
tsimport { Route } from 'vue-router' declare module 'vue' { interface ComponentCustomOptions { beforeRouteEnter?(to: any, from: any, next: () => void): void } }
TIP
Augmentations must be placed in a module
.ts
or.d.ts
file. See Type Augmentation Placement for more details.See also Guide - Augmenting Custom Options
ComponentCustomProps
Used to augment allowed TSX props in order to use non-declared props on TSX elements.
Example
tsdeclare module 'vue' { interface ComponentCustomProps { hello?: string } } export {}
tsx// now works even if hello is not a declared prop <MyComponent hello="world" />
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Augmentations must be placed in a module
.ts
or.d.ts
file. See Type Augmentation Placement for more details.
CSSProperties
Used to augment allowed values in style property bindings.
Example
Allow any custom CSS property
tsdeclare module 'vue' { interface CSSProperties { [key: `--${string}`]: string } }
tsx<div style={ { '--bg-color': 'blue' } }>
html<div :style="{ '--bg-color': 'blue' }"></div>
TIP
Augmentations must be placed in a module .ts
or .d.ts
file. See Type Augmentation Placement for more details.
See also
SFC <style>
tags support linking CSS values to dynamic component state using the v-bind
CSS function. This allows for custom properties without type augmentation.