fix(slots): prevent errors when slot is empty quasarframework#9547 (quasarframework#9984)

quasarframework#9547

Author: pdanpdan

ui/src/components/expansion-item/QExpansionItem.js

@@ -171,7 +171,7 @@ export default Vue.extend({
       let child
 
       if (this.$scopedSlots.header !== void 0) {
-        child = this.$scopedSlots.header().slice()
+        child = [].concat(this.$scopedSlots.header())
       }
       else {
         child = [

ui/src/components/popup-edit/QPopupEdit.js

@@ -132,7 +132,7 @@ export default Vue.extend({
         title = slot(this, 'title', this.title),
         child = this.$scopedSlots.default === void 0
           ? []
-          : this.$scopedSlots.default(this.defaultSlotScope).slice()
+          : [].concat(this.$scopedSlots.default(this.defaultSlotScope))
 
       title && child.unshift(
         h('div', { staticClass: 'q-dialog__title q-mt-sm q-mb-sm' }, [ title ])

ui/src/components/select/QSelect.js

@@ -869,7 +869,7 @@ export default Vue.extend({
       }
 
       if (this.$scopedSlots.selected !== void 0) {
-        return this.$scopedSlots.selected().slice()
+        return [].concat(this.$scopedSlots.selected())
       }
 
       if (this.useChips === true) {

ui/src/utils/slot.js

@@ -6,7 +6,7 @@ export function slot (vm, slotName, otherwise) {
 
 export function uniqueSlot (vm, slotName, otherwise) {
   return vm.$scopedSlots[slotName] !== void 0
-    ? vm.$scopedSlots[slotName]().slice()
+    ? [].concat(vm.$scopedSlots[slotName]())
     : otherwise
 }