feat: vanilla function resolves

packages/schema/src/schema.ts

@@ -1,6 +1,6 @@
 import type { Base as _Base, HtmlAttributes as _HtmlAttributes, Meta as _Meta, Noscript as _Noscript, Style as _Style, BaseBodyAttributes, BodyEvents, DataKeys, DefinedValueOrEmptyObject, HttpEventAttributes, LinkBase, Merge, MergeHead, MetaFlatInput, ScriptBase, Stringable } from 'zhead'
 import type { InnerContent, ResolvesDuplicates, TagPosition, TagPriority, TagUserProperties, TemplateParams } from './tags'
-import type { FalsyEntries, Never } from './util'
+import type { Falsey, MaybeFunction, Never, ResolvableValues } from './util'
 
 export type UserTagConfigWithoutInnerContent = TagPriority & TagPosition & ResolvesDuplicates & Never<InnerContent> & { processTemplateParams?: false } // only allow opt-out
 export type UserAttributesConfig = ResolvesDuplicates & TagPriority & Never<InnerContent & TagPosition>
@@ -54,22 +54,22 @@ export interface BaseMeta extends Omit<_Meta, 'content'> {
 
 export type EntryAugmentation = undefined | Record<string, any>
 
-export type MaybeFunctionEntries<T> = {
+export type MaybeEventFnHandlers<T> = {
   [key in keyof T]?: T[key] | ((e: Event) => void)
 }
 
 type TitleTemplateResolver = string | ((title?: string) => string | null)
 
-export type Title = string | FalsyEntries<({ textContent: string } & SchemaAugmentations['title']) | null>
+export type Title = MaybeFunction<number | string | Falsey> | ResolvableValues<({ textContent: string } & SchemaAugmentations['title'])>
 export type TitleTemplate = TitleTemplateResolver | null | ({ textContent: TitleTemplateResolver } & SchemaAugmentations['titleTemplate'])
-export type Base<E extends EntryAugmentation = Record<string, any>> = Partial<Merge<SchemaAugmentations['base'], FalsyEntries<_Base>>> & DefinedValueOrEmptyObject<E>
-export type Link<E extends EntryAugmentation = Record<string, any>> = FalsyEntries<LinkBase> & MaybeFunctionEntries<HttpEventAttributes> & DataKeys & SchemaAugmentations['link'] & DefinedValueOrEmptyObject<E>
-export type Meta<E extends EntryAugmentation = Record<string, any>> = FalsyEntries<BaseMeta> & DataKeys & SchemaAugmentations['meta'] & DefinedValueOrEmptyObject<E>
-export type Style<E extends EntryAugmentation = Record<string, any>> = FalsyEntries<_Style> & DataKeys & SchemaAugmentations['style'] & DefinedValueOrEmptyObject<E>
-export type Script<E extends EntryAugmentation = Record<string, any>> = FalsyEntries<ScriptBase> & MaybeFunctionEntries<HttpEventAttributes> & DataKeys & SchemaAugmentations['script'] & DefinedValueOrEmptyObject<E>
-export type Noscript<E extends EntryAugmentation = Record<string, any>> = FalsyEntries<_Noscript> & DataKeys & SchemaAugmentations['noscript'] & DefinedValueOrEmptyObject<E>
-export type HtmlAttributes<E extends EntryAugmentation = Record<string, any>> = FalsyEntries<HtmlAttr> & DataKeys & SchemaAugmentations['htmlAttrs'] & DefinedValueOrEmptyObject<E>
-export type BodyAttributes<E extends EntryAugmentation = Record<string, any>> = FalsyEntries<BodyAttr> & MaybeFunctionEntries<BodyEvents> & DataKeys & SchemaAugmentations['bodyAttrs'] & DefinedValueOrEmptyObject<E>
+export type Base<E extends EntryAugmentation = Record<string, any>> = Partial<Merge<SchemaAugmentations['base'], ResolvableValues<_Base>>> & DefinedValueOrEmptyObject<E>
+export type Link<E extends EntryAugmentation = Record<string, any>> = ResolvableValues<LinkBase> & MaybeEventFnHandlers<HttpEventAttributes> & DataKeys & SchemaAugmentations['link'] & DefinedValueOrEmptyObject<E>
+export type Meta<E extends EntryAugmentation = Record<string, any>> = ResolvableValues<BaseMeta> & DataKeys & SchemaAugmentations['meta'] & DefinedValueOrEmptyObject<E>
+export type Style<E extends EntryAugmentation = Record<string, any>> = ResolvableValues<_Style> & DataKeys & SchemaAugmentations['style'] & DefinedValueOrEmptyObject<E>
+export type Script<E extends EntryAugmentation = Record<string, any>> = ResolvableValues<ScriptBase> & MaybeEventFnHandlers<HttpEventAttributes> & DataKeys & SchemaAugmentations['script'] & DefinedValueOrEmptyObject<E>
+export type Noscript<E extends EntryAugmentation = Record<string, any>> = ResolvableValues<_Noscript> & DataKeys & SchemaAugmentations['noscript'] & DefinedValueOrEmptyObject<E>
+export type HtmlAttributes<E extends EntryAugmentation = Record<string, any>> = ResolvableValues<HtmlAttr> & DataKeys & SchemaAugmentations['htmlAttrs'] & DefinedValueOrEmptyObject<E>
+export type BodyAttributes<E extends EntryAugmentation = Record<string, any>> = ResolvableValues<BodyAttr> & MaybeEventFnHandlers<BodyEvents> & DataKeys & SchemaAugmentations['bodyAttrs'] & DefinedValueOrEmptyObject<E>
 
 export interface HeadUtils {
   /**

packages/schema/src/tags.ts

@@ -1,6 +1,6 @@
 import type { RuntimeMode } from './head'
 import type { Head } from './schema'
-import type { FalsyEntries } from './util'
+import type { ResolvableValues } from './util'
 
 export interface ResolvesDuplicates {
   /**
@@ -60,7 +60,7 @@ export interface TagPriority {
   tagPriority?: number | 'critical' | 'high' | 'low' | `before:${string}` | `after:${string}`
 }
 
-export type TagUserProperties = FalsyEntries<TagPriority & TagPosition & InnerContent & ResolvesDuplicates & ProcessesTemplateParams>
+export type TagUserProperties = ResolvableValues<TagPriority & TagPosition & InnerContent & ResolvesDuplicates & ProcessesTemplateParams>
 
 export type TagKey = keyof Head
 

packages/schema/src/util.ts

@@ -2,6 +2,10 @@ export type Never<T> = {
   [P in keyof T]?: never
 }
 
-export type FalsyEntries<T> = {
-  [key in keyof T]?: T[key] | null | false | undefined // false is soft deprecated
+export type MaybeFunction<T> = T | (() => T)
+
+export type Falsey = false | null | undefined
+
+export type ResolvableValues<T> = {
+  [key in keyof T]?: MaybeFunction<T[key] | Falsey>
 }

packages/shared/src/normalise.ts

@@ -65,6 +65,10 @@ export function normaliseProps<T extends HeadTag>(props: T['props'], virtual: bo
     }
 
     if (!virtual && !TagConfigKeys.has(k as string)) {
+      if (typeof props[k] === 'function' && !String(k).startsWith('on')) {
+        // @ts-expect-error untyped
+        props[k] = props[k]()
+      }
       const v = String(props[k])
       // data keys get special treatment, we opt for more verbose syntax
       const isDataKey = (k as string).startsWith('data-')
@@ -105,6 +109,11 @@ export function normaliseEntryTags<T extends object = Head>(e: HeadEntry<T>): He
       }
       continue
     }
+    else if (typeof v === 'function' && k !== 'titleTemplate') {
+      // resolve titles that may be functions
+      input[k] = v()
+      continue
+    }
     // @ts-expect-error untyped
     tags.push(normaliseTag(k as keyof Head, v, e))
   }

packages/unhead/src/optionalPlugins/inferSeoMetaPlugin.ts

@@ -72,6 +72,7 @@ export function InferSeoMetaPlugin(options: InferSeoMetaPluginOptions = {}) {
             if (description && !hasOgDescription) {
               let newOgDescription = options?.ogDescription || description
               if (typeof newOgDescription === 'function')
+                // @ts-expect-error untyped
                 newOgDescription = newOgDescription(title)
 
               if (newOgDescription) {

packages/vue/src/types/schema.ts

@@ -1,4 +1,4 @@
-import type { Base as _Base, Link as _Link, Meta as _Meta, Noscript as _Noscript, Script as _Script, Style as _Style, Title as _Title, TitleTemplate as _TitleTemplate, BaseBodyAttr, BaseHtmlAttr, BodyEvents, DataKeys, DefinedValueOrEmptyObject, EntryAugmentation, HeadEntryOptions, MaybeArray, MaybeFunctionEntries, MergeHead, MetaFlatInput, SchemaAugmentations, Unhead } from '@unhead/schema'
+import type { Base as _Base, Link as _Link, Meta as _Meta, Noscript as _Noscript, Script as _Script, Style as _Style, Title as _Title, TitleTemplate as _TitleTemplate, BaseBodyAttr, BaseHtmlAttr, BodyEvents, DataKeys, DefinedValueOrEmptyObject, EntryAugmentation, HeadEntryOptions, MaybeArray, MaybeEventFnHandlers, MergeHead, MetaFlatInput, SchemaAugmentations, Unhead } from '@unhead/schema'
 import type { Plugin, Ref } from 'vue'
 import type { MaybeComputedRef, MaybeComputedRefEntries, MaybeComputedRefEntriesOnly } from './util'
 
@@ -35,7 +35,7 @@ export type Style<E extends EntryAugmentation = Record<string, any>> = MaybeComp
 export type Script<E extends EntryAugmentation = Record<string, any>> = MaybeComputedRefEntries<_Script<E>>
 export type Noscript<E extends EntryAugmentation = Record<string, any>> = MaybeComputedRefEntries<_Noscript<E>>
 export type HtmlAttributes<E extends EntryAugmentation = Record<string, any>> = MaybeComputedRef<MaybeComputedRefEntries<HtmlAttr & DataKeys & SchemaAugmentations['htmlAttrs'] & DefinedValueOrEmptyObject<E>>>
-export type BodyAttributes<E extends EntryAugmentation = Record<string, any>> = MaybeComputedRef<MaybeComputedRefEntries<BodyAttr & DataKeys & SchemaAugmentations['bodyAttrs'] & DefinedValueOrEmptyObject<E>> & MaybeFunctionEntries<BodyEvents>>
+export type BodyAttributes<E extends EntryAugmentation = Record<string, any>> = MaybeComputedRef<MaybeComputedRefEntries<BodyAttr & DataKeys & SchemaAugmentations['bodyAttrs'] & DefinedValueOrEmptyObject<E>> & MaybeEventFnHandlers<BodyEvents>>
 
 export interface ReactiveHead<E extends MergeHead = MergeHead> {
   /**

packages/vue/src/types/util.ts

@@ -1,9 +1,9 @@
 import type { ComputedRef, Ref } from 'vue'
 
 // copied from @vueuse/shared
-export type MaybeReadonlyRef<T> = (() => T) | ComputedRef<T>
+export type MaybeReadonlyRef<T> = ComputedRef<T>
 export type MaybeComputedRef<T> = T | MaybeReadonlyRef<T> | Ref<T>
-export type MaybeComputedRefOrFalsy<T> = undefined | false | null | T | MaybeReadonlyRef<T> | Ref<T>
+export type MaybeComputedRefOrFalsy<T> = T | MaybeReadonlyRef<T> | Ref<T>
 
 /**
  * @deprecated Use MaybeComputedRefOrFalsy

test/unhead/ssr/ssr.test.ts

@@ -1,5 +1,5 @@
 import { renderSSRHead } from '@unhead/ssr'
-import { useSeoMeta } from 'unhead'
+import { useHead, useSeoMeta } from 'unhead'
 import { describe, it } from 'vitest'
 import { basicSchema } from '../../fixtures'
 import { createHeadWithContext } from '../../util'
@@ -33,7 +33,6 @@ describe('ssr', () => {
     const head = createHeadWithContext()
 
     head.push({
-      // @ts-expect-error handle numbers
       title: 12345,
     })
 
@@ -190,4 +189,29 @@ describe('ssr', () => {
       }
     `)
   })
+
+  it('title function', async () => {
+    const head = createHeadWithContext()
+
+    useHead({
+      title: 'my default title',
+    })
+
+    useHead({
+      title: () => {
+        return undefined
+      },
+    })
+
+    const ctx = await renderSSRHead(head)
+    expect(ctx).toMatchInlineSnapshot(`
+      {
+        "bodyAttrs": "",
+        "bodyTags": "",
+        "bodyTagsOpen": "",
+        "headTags": "<title>my default title</title>",
+        "htmlAttrs": "",
+      }
+    `)
+  })
 })