Vue 3 Advanced Features: Teleport, Fragments, Suspense Quiz Quiz

Challenge your understanding of advanced Vue 3 features like Teleport portals, fragment support, and the Suspense component for asynchronous rendering. Strengthen your Vue 3 skills by exploring component composition, template behaviors, and async component handling.

1. Using Teleport for Modal Placement

   When creating a modal dialog in Vue 3, how does the Teleport feature benefit the placement of the modal in the DOM structure?

   1. It only applies styles from the parent component to the modal.
   2. It prevents the modal from accessing any parent data.
   3. It allows rendering the modal's content outside of its parent component hierarchy.
   4. It fixes the modal at the bottom of the component tree.

   Explanation: Teleport enables you to render content, like modals, outside the parent DOM hierarchy, which is useful for overlays and dialogs. Option B is incorrect because Teleport does not force placement at the tree's bottom. Option C is wrong since Teleport does not restrict styling; CSS rules still apply based on DOM location. Option D is incorrect; Teleport does not block parent data access—props and slots still pass normally.

2. Understanding Fragments in Vue 3

   How does Vue 3's support for fragments affect the structure of a component's template output?

   1. It merges sibling elements' attributes by default.
   2. It requires all templates to have a single root element.
   3. It allows multiple root elements without an extra wrapper node.
   4. It automatically adds a u003Cfragmentu003E tag around all root elements.

   Explanation: Fragments let you write components with multiple top-level elements in Vue 3 without an additional wrapper. Option B is incorrect as that was a limitation in earlier versions. Option C is incorrect because there is no fragment tag inserted. Option D is wrong and misleading; sibling elements do not have their attributes merged.

3. Purpose of the Suspense Component

   What is the primary purpose of the Suspense component in Vue 3 when working with async components?

   1. It caches async data after the first load for all users.
   2. It blocks JavaScript execution until components finish loading.
   3. It displays fallback content while async components are loading.
   4. It defers initial rendering until all stylesheets are loaded.

   Explanation: Suspense provides a mechanism for displaying fallback content while awaiting the resolution of async components. Option B is incorrect, as Suspense does not handle stylesheet loading. Option C is wrong since Suspense does not cache data globally; caching must be handled separately. Option D is not accurate because Suspense does not block overall JavaScript execution.

4. Teleport and Reactivity Boundaries

   If you use Teleport to move a child component outside its parent in the DOM, how does it affect Vue’s reactivity between parent and child components?

   1. Parent events cannot be emitted from the teleported child.
   2. Reactivity is fully preserved; Teleport only moves the DOM node.
   3. Teleport duplicates the child component rendering in both locations.
   4. Reactivity is broken, and data is not shared between parent and child.

   Explanation: Teleport only moves how content is presented in the DOM, keeping the component hierarchy and reactivity intact. Option B is false; data flow between parent and child works as usual. Option C is incorrect since Teleport does not duplicate rendering but moves it instead. Option D is doubtful, as events can still be emitted from the teleported child as usual.

5. Using Suspense with Nested Components

   Suppose you have a Suspense component wrapping a tree of nested components, with one deeply nested child being loaded asynchronously; what happens to the fallback content?

   1. The fallback content is ignored if only nested components are async.
   2. The fallback content is replaced by a loading spinner by default.
   3. The fallback content only flashes for a split second regardless of actual loading time.
   4. The fallback content is shown until all async dependencies inside the Suspense tree are resolved.

   Explanation: Suspense will show the fallback content until every async component within its subtree is ready. Option B is inaccurate as the display duration depends on the loading time. Option C is incorrect; Suspense works with any async descendants, not just direct children. Option D is wrong; a loading spinner is not the default—fallback is defined by the developer.