fix(Select/SelectMenu): prevent empty string display when multiple

Regression of 7df7ee336a

docs/app/components/content/examples/form/FormExampleElements.vue

@@ -15,6 +15,9 @@ const schema = z.object({
   select: z.string().refine(value => value === 'option-2', {
     message: 'Select Option 2'
   }),
+  selectMultiple: z.array(z.string()).refine(values => values.includes('option-2'), {
+    message: 'Include Option 2'
+  }),
   selectMenu: z.any().refine(option => option?.value === 'option-2', {
     message: 'Select Option 2'
   }),
@@ -81,6 +84,10 @@ async function onSubmit(event: FormSubmitEvent<Schema>) {
         <USelect v-model="state.select" :items="items" class="w-full" />
       </UFormField>
 
+      <UFormField name="selectMultiple" label="Select (Multiple)">
+        <USelect v-model="state.selectMultiple" multiple :items="items" class="w-full" />
+      </UFormField>
+
       <UFormField name="selectMenu" label="Select Menu">
         <USelectMenu v-model="state.selectMenu" :items="items" class="w-full" />
       </UFormField>

src/runtime/components/Select.vue

@@ -193,9 +193,10 @@ const groups = computed<SelectItem[][]>(() =>
 // eslint-disable-next-line vue/no-dupe-keys
 const items = computed(() => groups.value.flatMap(group => group) as T[])
 
-function displayValue(value?: GetItemValue<T, VK> | GetItemValue<T, VK>[]): string {
+function displayValue(value: GetItemValue<T, VK> | GetItemValue<T, VK>[]): string | undefined {
   if (props.multiple && Array.isArray(value)) {
-    return value.map(v => displayValue(v)).filter(Boolean).join(', ')
+    const values = value.map(v => displayValue(v)).filter(Boolean)
+    return values?.length ? values.join(', ') : undefined
   }
 
   const item = items.value.find(item => compare(typeof item === 'object' ? get(item as Record<string, any>, props.valueKey as string) : item, value))

src/runtime/components/SelectMenu.vue

@@ -225,9 +225,10 @@ const ui = computed(() => tv({ extend: tv(theme), ...(appConfig.ui?.selectMenu |
   buttonGroup: orientation.value
 }))
 
-function displayValue(value: GetItemValue<T, VK> | GetItemValue<T, VK>[]): string {
+function displayValue(value: GetItemValue<T, VK> | GetItemValue<T, VK>[]): string | undefined {
   if (props.multiple && Array.isArray(value)) {
-    return value.map(v => displayValue(v)).filter(Boolean).join(', ')
+    const values = value.map(v => displayValue(v)).filter(Boolean)
+    return values?.length ? values.join(', ') : undefined
   }
 
   if (!props.valueKey) {

test/components/__snapshots__/Select-vue.spec.ts.snap

@@ -456,7 +456,7 @@ exports[`Select > renders with modelValue correctly 1`] = `
 
 exports[`Select > renders with multiple and modelValue correctly 1`] = `
 "<button class="relative group rounded-md inline-flex items-center focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors px-2.5 py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary pe-9" role="combobox" type="button" aria-controls="reka-select-content-v-0" aria-expanded="true" aria-required="false" aria-autocomplete="none" dir="ltr" data-state="open">
-  <!--v-if--><span class="truncate pointer-events-none"></span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 text-dimmed size-5"></svg></span>
+  <!--v-if--><span class="truncate text-dimmed">&nbsp;</span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 text-dimmed size-5"></svg></span>
 </button>
 <!--teleport start-->
 
@@ -483,7 +483,7 @@ exports[`Select > renders with multiple and modelValue correctly 1`] = `
 
 exports[`Select > renders with multiple correctly 1`] = `
 "<button class="relative group rounded-md inline-flex items-center focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors px-2.5 py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary pe-9" role="combobox" type="button" aria-controls="reka-select-content-v-0" aria-expanded="true" aria-required="false" aria-autocomplete="none" dir="ltr" data-state="open" data-placeholder="">
-  <!--v-if--><span class="truncate pointer-events-none"></span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 text-dimmed size-5"></svg></span>
+  <!--v-if--><span class="truncate text-dimmed">&nbsp;</span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 text-dimmed size-5"></svg></span>
 </button>
 <!--teleport start-->
 

test/components/__snapshots__/Select.spec.ts.snap

@@ -456,7 +456,7 @@ exports[`Select > renders with modelValue correctly 1`] = `
 
 exports[`Select > renders with multiple and modelValue correctly 1`] = `
 "<button class="relative group rounded-md inline-flex items-center focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors px-2.5 py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary pe-9" role="combobox" type="button" aria-controls="reka-select-content-v-0-0-0" aria-expanded="true" aria-required="false" aria-autocomplete="none" dir="ltr" data-state="open">
-  <!--v-if--><span class="truncate pointer-events-none"></span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><span class="iconify i-lucide:chevron-down shrink-0 text-dimmed size-5" aria-hidden="true"></span></span>
+  <!--v-if--><span class="truncate text-dimmed">&nbsp;</span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><span class="iconify i-lucide:chevron-down shrink-0 text-dimmed size-5" aria-hidden="true"></span></span>
 </button>
 <!--teleport start-->
 
@@ -483,7 +483,7 @@ exports[`Select > renders with multiple and modelValue correctly 1`] = `
 
 exports[`Select > renders with multiple correctly 1`] = `
 "<button class="relative group rounded-md inline-flex items-center focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors px-2.5 py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary pe-9" role="combobox" type="button" aria-controls="reka-select-content-v-0-0-0" aria-expanded="true" aria-required="false" aria-autocomplete="none" dir="ltr" data-state="open" data-placeholder="">
-  <!--v-if--><span class="truncate pointer-events-none"></span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><span class="iconify i-lucide:chevron-down shrink-0 text-dimmed size-5" aria-hidden="true"></span></span>
+  <!--v-if--><span class="truncate text-dimmed">&nbsp;</span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><span class="iconify i-lucide:chevron-down shrink-0 text-dimmed size-5" aria-hidden="true"></span></span>
 </button>
 <!--teleport start-->
 

test/components/__snapshots__/SelectMenu-vue.spec.ts.snap

@@ -685,7 +685,7 @@ exports[`SelectMenu > renders with multiple and modelValue correctly 1`] = `
 
 exports[`SelectMenu > renders with multiple correctly 1`] = `
 "<button type="button" tabindex="0" aria-label="Show popup" aria-haspopup="listbox" aria-expanded="true" aria-controls="" data-state="open" aria-disabled="false" dir="ltr" style="pointer-events: auto;" class="relative group rounded-md inline-flex items-center focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors px-2.5 py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary pe-9">
-  <!--v-if--><span class="truncate pointer-events-none"></span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 text-dimmed size-5"></svg></span>
+  <!--v-if--><span class="truncate text-dimmed">&nbsp;</span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 text-dimmed size-5"></svg></span>
 </button>
 <!--teleport start-->
 

test/components/__snapshots__/SelectMenu.spec.ts.snap

@@ -685,7 +685,7 @@ exports[`SelectMenu > renders with multiple and modelValue correctly 1`] = `
 
 exports[`SelectMenu > renders with multiple correctly 1`] = `
 "<button type="button" tabindex="0" aria-label="Show popup" aria-haspopup="listbox" aria-expanded="true" aria-controls="" data-state="open" aria-disabled="false" dir="ltr" style="pointer-events: auto;" class="relative group rounded-md inline-flex items-center focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors px-2.5 py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary pe-9">
-  <!--v-if--><span class="truncate pointer-events-none"></span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><span class="iconify i-lucide:chevron-down shrink-0 text-dimmed size-5" aria-hidden="true"></span></span>
+  <!--v-if--><span class="truncate text-dimmed">&nbsp;</span><span class="absolute inset-y-0 end-0 flex items-center pe-2.5"><span class="iconify i-lucide:chevron-down shrink-0 text-dimmed size-5" aria-hidden="true"></span></span>
 </button>
 <!--teleport start-->