(1/20) Which advanced pattern might you adopt to fully isolate watchers inside a child’s effect scope so that the parent can force a re-creation or teardown of that child’s reactivity in Vue 3?

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• Use watchers in main.js for concurrency watchers only
• Impossible to isolate watchers with effect scope
• Use defineProps for concurrency watchers
• The child can define createEffectScope within setup, then run watchers inside that scope. The parent can call scope.stop() if the child exposes that scope or on unmount. This is advanced usage, but possible

(2/20) Which new directive in Vue 3.3 allows you to skip updates if certain dependencies haven't changed, used like <template v-memo="[someDependency]">?

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• v-show
• v-if
• v-once
• v-memo

(3/20) Which advanced lifecycle might you rely on if you need to manipulate the final rendered markup in a custom SSR pipeline for Vue 3, hooking into just after the entire app’s HTML is generated but before sending to the client?

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• A custom renderer using @vue/server-renderer with a post-processing hook or final transform, because Vue does not provide a built-in lifecycle for post-SSR manipulations in the standard API
• No approach for post-render manipulation in SSR
• onMounted in SSR
• Use watchers in concurrency watchers mode only

(4/20) Which approach might you take if your watchers in Vue 3 keep re-running because you mutate a deeply nested property on each callback, causing a re-render loop?

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• Avoid mutating the same property the watcher is tracking without condition checks, or store the data in a separate, non-reactive structure if you must mutate it, or do minimal changes to prevent infinite loops
• Use defineExpose for concurrency watchers
• Impossible to fix re-render loops
• Use watchers in main.js for concurrency watchers only

(5/20) When migrating from Vue 2 to Vue 3, which helper from the Vue 2 composition plugin is replaced by the official Composition API?

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• Vue.extend
• vue-function-api plugin
• setupComponent
• createComponent

(6/20) When using script setup, how do you force a property or method to remain private to the component so that it cannot be accessed via template refs in the parent?

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• Return the property from setup() explicitly
• Use defineExpose() and omit that property from the exposed object
• All properties in script setup are automatically public
• You must define it as a global variable

(7/20) Which statement about watchers referencing a shallowReactive object in Vue 3 is accurate if you mutate nested fields within that object?

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• Use watchers in main.js for concurrency watchers only
• Triggers watchers automatically at deep levels
• No watchers trigger for nested fields because shallowReactive only tracks top-level property assignments
• Use defineProps for concurrency watchers

(8/20) When using defineAsyncComponent in Vue 3, which lifecycle hook or event can you use to detect when the async component has failed to load?

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• onBeforeLoad in the child
• onErrorCaptured in the parent
• There is no way to detect load failures
• asyncLoadFailure

(9/20) In Vue 3’s Composition API, what is the difference between watchPostEffect() and watchEffect()?

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• watchEffect() only runs once, watchPostEffect() runs repeatedly
• watchPostEffect() defers its callback until after DOM updates, while watchEffect() runs before DOM patching
• They are synonyms and do the same thing
• watchPostEffect() only works with reactive arrays

(10/20) How can you define a local directive in a Vue 3 component using <script setup> if you want it recognized only in this component’s template?

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• Local directives are not recognized in <script setup>
• Use watchers in the main.js for directive hooking
• Define it in defineExpose
• Create a directive object in the script, then apply it in the template with v-myDirective, and rely on bundler auto-detection of local usage

(11/20) Which optimization does Vue 3’s compiler apply to v-for blocks that do not rely on reactivity within the iteration scope, for performance gains?

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• Manual watchers only
• v-for is replaced by watchers in concurrency
• It can hoist the static parts out of the render function if the loop body is partially or fully static, reducing patch overhead
• No approach for optimizing v-for in Vue 3

(12/20) How might you unify watchers for concurrency in an advanced scenario where both a local and a global store property must be consistent, and changes in either must invalidate the other’s async tasks in Vue 3?

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• Define watchers in both local and store. Each has onInvalidate. Or place them in a shared effect scope that references both local state and store state, watching [() => local, () => storeProp]. If one changes, you invalidate the other’s ongoing operation. This is advanced multi-source concurrency
• Impossible to unify local + global concurrency
• Use watchers in main.js for concurrency watchers only
• Use defineProps for concurrency watchers

(13/20) If you have a custom v-model prop name, how do you consume it in a child component in Vue 3?

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• You can define v-model:myPropName, which expects prop 'myPropName' and event 'update:myPropName'
• Custom v-model is disallowed in Vue 3
• By default it’s always modelValue and update:modelValue
• Use watchers for the changed property name

(14/20) How can you access props within the setup() function in Vue 3 using the Options API style component definition?

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• You must define them in data() first
• Props are automatically available as this.props in setup()
• You cannot use props in the setup() function
• Props are destructured from the second argument of setup(props, context)

(15/20) When using watchers for concurrency in a parent passing data to child components in Vue 3, how do you ensure the child only updates after the parent watchers finish?

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• Because watchers run in the parent's update cycle, the child's props are updated after that. You can set flush: 'post' if you want the watch callback to run after DOM patch, but the child's props still see the new data next tick. There's no direct mechanism to block the child's update aside from controlling the data flow
• Impossible to sequence watchers across parent and child
• Use watchers in main.js for concurrency watchers only
• Use defineProps for concurrency watchers

(16/20) Which of the following is a potential downside of using provide/inject in Vue 3?

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• They don’t support reactive data
• They automatically cause memory leaks
• They can create tight coupling if misused
• They cannot be typed with TypeScript

(17/20) Which statement best describes how <Suspense> can handle multiple async children in Vue 3?

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• Suspense only supports one async child
• It merges watchers for all children automatically
• All children must resolve individually; once they all resolve, the fallback is replaced by the default slot
• It toggles SSR mode forcibly

(18/20) What is the purpose of 'Suspense boundary' in a Vue 3 application?

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• It allows you to show a fallback while child components (or async setup) are not yet resolved
• It wraps watchers for concurrency control
• It is used only for global events
• It replaces keep-alive in Vue 3

(19/20) How can you define advanced typed route guards in a Vue 3 SSR environment, ensuring your custom route.meta fields are recognized during server-side navigation checks?

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• Impossible to run route guards in SSR
• Use watchers in main.js for concurrency watchers only
• Use defineProps for concurrency watchers
• Augment RouteMeta in a .d.ts, define SSR-based checks in onBeforeRouteEnter or global guards. On the server, ensure you handle route.meta within your custom server logic or plugin

(20/20) When might you call app.unmount() in a Vue 3 application?

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• To define watchers globally
• If you want to destroy the root app instance from the DOM manually, e.g. single-page teardown or dynamic mounting/unmounting
• Vue 3 does not allow unmounting
• It merges watchers for concurrency only

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