Merge branch 'main' of github.com:unjs/unhead

Author: harlan-zw

packages/unhead/src/plugins/dedupe.ts

@@ -36,12 +36,16 @@ export default defineHeadPlugin({
             const oldProps = dupedTag.props
             // apply oldProps to current props
             ;['class', 'style'].forEach((key) => {
-              if (tag.props[key] && oldProps[key]) {
-                // ensure style merge doesn't result in invalid css
-                if (key === 'style' && !oldProps[key].endsWith(';'))
-                  oldProps[key] += ';'
+              if(oldProps[key]) {
+                if (tag.props[key]) {
+                  // ensure style merge doesn't result in invalid css
+                  if (key === 'style' && !oldProps[key].endsWith(';'))
+                    oldProps[key] += ';'
 
-                tag.props[key] = `${oldProps[key]} ${tag.props[key]}`
+                  tag.props[key] = `${oldProps[key]} ${tag.props[key]}`
+                } else {
+                  tag.props[key] = oldProps[key]
+                }
               }
             })
             deduping[dedupeKey].props = {

test/vue/resolveTags.test.ts

@@ -109,4 +109,57 @@ describe('resolveTags', () => {
       ]
     `)
   })
+  it('resolve multiple conditional classes entries', async () => {
+    const head = createHead()
+    setHeadInjectionHandler(() => head)
+
+    useHead({
+      htmlAttrs: {
+        class: {
+          someTrue: true,
+        },
+      },
+    })
+
+    useHead({
+      htmlAttrs: {
+        class: ['someArrayClass'],
+      },
+    })
+
+    useHead({
+      htmlAttrs: {
+        class: {
+          someFalsy: false,
+        },
+      },
+    })
+
+    useHead({
+      htmlAttrs: {
+        class: [],
+      },
+    })
+
+    useHead({
+      htmlAttrs: {
+        class: '',
+      },
+    })
+
+    const tags = await head.resolveTags()
+    expect(tags).toMatchInlineSnapshot(`
+      [
+        {
+          "_d": "htmlAttrs",
+          "_e": 0,
+          "_p": 0,
+          "props": {
+            "class": "someTrue someArrayClass",
+          },
+          "tag": "htmlAttrs",
+        },
+      ]
+    `)
+  })
 })