vue-debug-guides

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---
name: vue-debug-guides
description: Vue 3 debugging and error handling for runtime errors, warnings, async failures, and SSR/hydration issues. Use when diagnosing or fixing Vue issues.
---

Vue 3 debugging and error handling for runtime issues, warnings, async failures, and hydration bugs.
For development best practices and common gotchas, use `vue-best-practices`.

### Reactivity
- Tracing unexpected re-renders and state updates → See [reactivity-debugging-hooks](reference/reactivity-debugging-hooks.md)
- Ref values not updating due to missing .value access → See [ref-value-access](reference/ref-value-access.md)
- State stops updating after destructuring reactive objects → See [reactive-destructuring](reference/reactive-destructuring.md)
- Refs inside arrays, Maps, or Sets not unwrapping → See [refs-in-collections-need-value](reference/refs-in-collections-need-value.md)
- Nested refs rendering as [object Object] in templates → See [template-ref-unwrapping-top-level](reference/template-ref-unwrapping-top-level.md)
- Reactive proxy identity comparisons always return false → See [reactivity-proxy-identity-hazard](reference/reactivity-proxy-identity-hazard.md)
- Third-party instances breaking when proxied → See [reactivity-markraw-for-non-reactive](reference/reactivity-markraw-for-non-reactive.md)
- Watchers only firing once per tick unexpectedly → See [reactivity-same-tick-batching](reference/reactivity-same-tick-batching.md)

### Computed
- Computed getter triggers mutations or requests unexpectedly → See [computed-no-side-effects](reference/computed-no-side-effects.md)
- Mutating computed values causes changes to disappear → See [computed-return-value-readonly](reference/computed-return-value-readonly.md)
- Computed value never updates after conditional logic → See [computed-conditional-dependencies](reference/computed-conditional-dependencies.md)
- Sorting or reversing arrays breaks original state → See [computed-array-mutation](reference/computed-array-mutation.md)
- Passing parameters to computed properties fails → See [computed-no-parameters](reference/computed-no-parameters.md)

### Watchers
- Async operations overwriting with stale data → See [watch-async-cleanup](reference/watch-async-cleanup.md)
- Creating watchers inside async callbacks → See [watch-async-creation-memory-leak](reference/watch-async-creation-memory-leak.md)
- Watcher never triggers for reactive object properties → See [watch-reactive-property-getter](reference/watch-reactive-property-getter.md)
- Async watchEffect misses dependencies after await → See [watcheffect-async-dependency-tracking](reference/watcheffect-async-dependency-tracking.md)
- DOM reads are stale inside watcher callbacks → See [watch-flush-timing](reference/watch-flush-timing.md)
- Deep watchers report identical old/new values → See [watch-deep-same-object-reference](reference/watch-deep-same-object-reference.md)
- watchEffect runs before template refs update → See [watcheffect-flush-post-for-refs](reference/watcheffect-flush-post-for-refs.md)

### Components
- Child component throws "component not found" error → See [local-components-not-in-descendants](reference/local-components-not-in-descendants.md)
- Click listener doesn't fire on custom component → See [click-events-on-components](reference/click-events-on-components.md)
- Parent can't access child ref data in script setup → See [component-ref-requires-defineexpose](reference/component-ref-requires-defineexpose.md)
- HTML template parsing breaks Vue component syntax → See [in-dom-template-parsing-caveats](reference/in-dom-template-parsing-caveats.md)
- Wrong component renders due to naming collisions → See [component-naming-conflicts](reference/component-naming-conflicts.md)
- Parent styles don't apply to multi-root component → See [multi-root-component-class-attrs](reference/multi-root-component-class-attrs.md)

### Props & Emits
- Variables referenced in defineProps cause errors → See [prop-defineprops-scope-limitation](ref