Vue 3 best practices, common gotchas, and performance optimization.

Reactivity

• Accessing ref() values without .value in scripts → See ref-value-access

• Destructuring reactive() objects, losing reactivity → See reactive-destructuring

• Choosing between ref() and reactive() for state → See prefer-ref-over-reactive

• Accessing refs inside arrays and collections → See refs-in-collections-need-value

• Large objects or external library data overhead → See shallow-ref-for-performance

• Using nested refs in template expressions → See template-ref-unwrapping-top-level

• Comparing reactive objects with === operator → See reactivity-proxy-identity-hazard

• Library instances breaking in reactive state → See reactivity-markraw-for-non-reactive

• Expecting watchers to fire for each state change → See reactivity-same-tick-batching

• Integrating external state management libraries → See reactivity-external-state-integration

• Deriving state with watchEffect instead of computed → See reactivity-computed-over-watcheffect-mutations

Computed

• Computed getter is making API calls or mutations → See computed-no-side-effects

• Mutating computed values causes lost changes unexpectedly → See computed-return-value-readonly

• Computed property doesn't update when expected → See computed-conditional-dependencies

• Sorting or reversing arrays destroys original data → See computed-array-mutation

• Expensive operations running too frequently every render → See computed-vs-methods-caching

• Trying to pass arguments to computed properties → See computed-no-parameters

• Complex conditions bloating inline class bindings → See computed-properties-for-class-logic

Watchers

• Need to watch a reactive object property → See watch-reactive-property-getter

• Large nested data structures causing performance issues → See watch-deep-performance

• Dependencies accessed after await not tracking → See watcheffect-async-dependency-tracking

• Need to access updated DOM in watchers → See watch-flush-timing

• Uncertain whether to use watch or watchEffect → See watch-vs-watcheffect

• Duplicating initial calls and watch callbacks → See watch-immediate-option

• Can't compare old and new values correctly → See watch-deep-same-object-reference

• Template refs appearing null or stale → See watcheffect-flush-post-for-refs

Components

• Prop values being changed from a child component → See props-are-read-only

• Grandparent can't listen to grandchild emitted events → See component-events-dont-bubble

• Distinguishing Vue components from native elements → See component-naming-pascalcase

• Recursive component needs to reference itself → See self-referencing-component-name

• Bundle includes components that aren't used → See prefer-local-component-registration

• Tight coupling through component ref access → See prefer-props-emit-over-component-refs

Props & Emits

• Boolean prop not parsing as expected → See prop-boolean-casting-order

• Composable doesn't update when props change → See prop-composable-reactivity-loss

• Destructured props not updating watchers → See prop-destructured-watch-getter

• Prop validation needs component instance data → See prop-validation-before-instance

• Event name inconsistency in templates and scripts → See emit-kebab-case-in-templates

• Event payloads need validation during development → See emit-validation-for-complex-payloads

Templates

• Rendering untrusted user content as HTML → See v-html-xss-security

• Filtering or conditionally hiding list items → See no-v-if-with-v-for

• Functions in templates modifying data unexpectedly → See template-functions-no-side-effects

• Performance issues with filtered or sorted lists → See v-for-use-computed-for-filtering

• Deciding between v-if and v-show for conditionals → See v-if-vs-v-show-performance

Forms & v-model

• Need to handle v-model modifiers in child → See definemodel-hidden-modifier-props

• Need to use updated value immediately after change → See definemodel-value-next-tick

• Migrating Vue 2 components to Vue 3 → See v-model-vue3-breaking-changes

Events & Modifiers

• Need to handle same event only one time → See event-once-modifier-for-single-use

• Keyboard shortcuts fire with unintended modifier combinations → See exact-modifier-for-precise-shortcuts

• Using left-handed mouse or non-standard input devices → See mouse-button-modifiers-intent

• Preventing default browser action and scroll performance together → See no-passive-with-prevent

Lifecycle

• Lifecycle hooks don't execute asynchronously → See lifecycle-hooks-synchronous-registration

• Expensive operations slow performance drastically → See updated-hook-performance

Slots

• Accessing child component data in slot content → See slot-render-scope-parent-only

• Mixing named and scoped slots together → See slot-named-scoped-explicit-default

• Using v-slot on native HTML elements → See slot-v-slot-on-components-or-templates-only

• Empty wrapper elements rendering unnecessarily → See slot-conditional-rendering-with-slots

• Scoped slot props lack TypeScript type safety → See slot-define-slots-for-typescript

• Rendering empty component slots without defaults → See slot-fallback-content-default-values

• Confused about which slot content goes where → See slot-implicit-default-content

• Expecting name property in scoped slot props → See slot-name-reserved-prop

• Choosing between renderless components and composables → See slot-renderless-components-vs-composables

Provide/Inject

• String keys collide in large applications → See provide-inject-symbol-keys

• State mutations scattered across components → See provide-inject-mutations-in-provider

• Passing props through many component layers → See avoid-prop-drilling-use-provide-inject

Attrs

• Accessing hyphenated attributes in JavaScript code → See attrs-hyphenated-property-access

• Watching fallthrough attributes for changes with watch() → See attrs-not-reactive

Composables

• Composable has unexpected side effects affecting external state → See composable-avoid-hidden-side-effects

• Building complex logic from smaller focused composables → See composable-composition-pattern

• Inconsistent composable names or destructuring loses reactivity → See composable-naming-return-pattern

• Composable has many optional parameters or confusing argument order → See composable-options-object-pattern

• Need to prevent uncontrolled mutations of composable state → See composable-readonly-state

• Unsure whether logic belongs in composable or utility function → See composable-vs-utility-functions

Composition API

• Optimizing production bundle size and performance → See composition-api-bundle-size-minification

• Composition API code becoming scattered and hard to maintain → See composition-api-code-organization

• Fixing naming conflicts and unclear data origins in mixins → See composition-api-mixins-replacement

• Applying functional patterns incorrectly to Vue state → See composition-api-not-functional-programming

• Gradually migrating large Options API codebase → See composition-api-options-api-coexistence

• Coming from React, over-engineering Vue patterns unnecessarily → See composition-api-vs-react-hooks-differences

Directives

• Storing state across directive hooks → See directive-arguments-read-only

• Applying custom directives to Vue components → See directive-avoid-on-components

• Creating intervals or event listeners in directives → See directive-cleanup-in-unmounted

• Simplifying directives with identical behavior → See directive-function-shorthand

• Using custom directives in script setup → See directive-naming-v-prefix

• Choosing between custom and built-in directives → See directive-prefer-declarative-templating

• Deciding between directives and components → See directive-vs-component-decision

• Migrating Vue 2 directives to Vue 3 → See directive-vue2-migration-hooks

Transitions

• Wrapping multiple elements or components in transitions → See transition-single-element-slot

• Transitioning between same element types without animation → See transition-key-for-same-element

• Using JavaScript animations without calling done callback → See transition-js-hooks-done-callback

• Animating lists with TransitionGroup without unique keys → See transition-group-key-requirement

• Performance problems with janky list animations → See transition-animate-transform-opacity

• Move animations failing on inline list elements → See transition-group-flip-inline-elements

• List items jumping instead of smoothly animating → See transition-group-move-animation-position-absolute

• Vue 2 to Vue 3 transition layout breaks unexpectedly → See transition-group-no-default-wrapper-vue3

• Trying to sequence list animations with mode prop → See transition-group-no-mode-prop

• Creating cascading delays for list item animations → See transition-group-staggered-animations

• Overlapping elements or layout jumping during transitions → See transition-mode-out-in

• Nested transition animations cutting off prematurely → See transition-nested-duration

• Reusable transition components with scoped styles breaking → See transition-reusable-scoped-style

• RouterView transitions unexpectedly animating on page load → See transition-router-view-appear

• Mixing CSS transitions and animations causing timing issues → See transition-type-when-mixed

• Component cleanup not firing during fast transition replacements → See transition-unmount-hook-timing

Animation

• Need to animate elements staying in DOM → See animation-class-based-technique

• Animations not triggering on content changes → See animation-key-for-rerender

• Building interactive animations with user input → See animation-state-driven-technique

• Animating list changes causing noticeable lag → See animation-transitiongroup-performance

KeepAlive

• Using KeepAlive without proper cache limits or cleanup → See keepalive-memory-management

• KeepAlive include/exclude props not matching cached components → See keepalive-component-name-requirement

• Need to programmatically remove component from KeepAlive cache → See keepalive-no-cache-removal-vue3

• Users see stale cached content when expecting fresh page data → See keepalive-router-fresh-vs-cached

• Child components mount twice with nested Vue Router routes → See keepalive-router-nested-double-mount

• Memory grows when combining KeepAlive with Transition animations → See keepalive-transition-memory-leak

• Dynamic component state resets when switching between them → See dynamic-components-with-keepalive

Async Components

• Setting up Vue Router route component loading → See async-component-vue-router

• Async component options ignored by parent Suspense → See async-component-suspense-control

• Improving Time to Interactive with SSR apps → See async-component-hydration-strategies

• Loading spinner flashing on fast networks → See async-component-loading-delay

Render Functions

• Render function from setup doesn't update reactively → See rendering-render-function-return-from-setup

• Same vnode appearing multiple times in tree → See render-function-vnodes-must-be-unique

• Rendering lists in render functions without keys → See render-function-v-for-keys-required

• Implementing .stop, .prevent in render functions → See render-function-event-modifiers

• Two-way binding on components in render functions → See render-function-v-model-implementation

• Using string names for components in render functions → See rendering-resolve-component-for-string-names

• Accessing vnode internals like el or shapeFlag → See render-function-avoid-internal-vnode-properties

• Creating simple stateless presentational components → See render-function-functional-components

• Applying custom directives in render functions → See render-function-custom-directives

• Excessive rerenders from watchers or deep watchers → See rendering-excessive-rerenders-watch-vs-computed

• Choosing render functions over templates → See rendering-prefer-templates-over-render-functions

• Migrating Vue 2 render functions to Vue 3 → See rendering-render-function-h-import-vue3

• Passing slot content to h() incorrectly → See rendering-render-function-slots-as-functions

• Understanding Vue's vdom optimization blocks → See rendering-understand-vdom-block-structure

Teleport

• Modal breaks with parent CSS transforms → See teleport-css-positioning-issues

• Content needs different layout on mobile → See teleport-disabled-for-responsive

• Unsure if props/events work through teleport → See teleport-logical-hierarchy-preserved

• Multiple modals targeting same container → See teleport-multiple-to-same-target

• Scoped styles not applying to teleported content → See teleport-scoped-styles-limitation

Suspense

• Want to track Suspense loading states programmatically → See suspense-events-for-state-tracking

• Planning Suspense usage in production applications → See suspense-experimental-api-stability

• Fallback not showing when content changes → See suspense-fallback-not-immediate-on-revert

• Nesting Suspense components together → See suspense-nested-suspensible-prop

• Combining Suspense with Router, Transition, KeepAlive → See suspense-nesting-order-with-router

• Nested async component not showing loading indicator → See suspense-revert-only-on-root-change

• Multiple async components in single Suspense → See suspense-single-child-requirement

TypeScript

• Declaring props with TypeScript in composition API components → See ts-defineprops-type-based-declaration

• Providing default values to mutable prop types → See ts-withdefaults-mutable-factory-function

• Typing reactive state with ref unwrapping concerns → See ts-reactive-no-generic-argument

• Accessing DOM elements after component mounts → See ts-template-ref-null-handling

• Typing refs to child Vue components → See ts-component-ref-typeof-instancetype

• Using custom directives with TypeScript support → See ts-custom-directive-type-augmentation

• Declaring component events with full type safety → See ts-defineemits-type-based-syntax

• Handling optional boolean props in TypeScript → See ts-defineprops-boolean-default-false

• Using imported types safely in defineProps → See ts-defineprops-imported-types-limitations

• Handling DOM events with strict TypeScript checking → See ts-event-handler-explicit-typing

• Sharing data between components with type safety → See ts-provide-inject-injection-key

• Storing Vue components in reactive state → See ts-shallowref-for-dynamic-components

• Working with union types in Vue templates → See ts-template-type-casting

SSR

• User data leaking between server requests → See state-ssr-cross-request-pollution

• Code runs on both server and browser environments → See ssr-platform-specific-apis

• Custom directives not displaying on server-rendered HTML → See ssr-custom-directive-getssrprops

Performance

• Many list items re-rendering unnecessarily during state changes → See perf-props-stability-update-optimization

• Rendering hundreds or thousands of items causing DOM performance issues → See perf-virtualize-large-lists

• Static content re-evaluated on every parent component update → See perf-v-once-v-memo-directives

• List performance degrading from deeply nested component structure → See perf-avoid-component-abstraction-in-lists

• Computed properties returning objects triggering effects unexpectedly → See perf-computed-object-stability

• Page load metrics suffering from client-side JavaScript execution delay → See perf-ssr-ssg-for-page-load

SFC (Single File Components)

• Starting a Vue project with a build setup → See sfc-recommended-for-build-projects

• Styling child component elements with scoped CSS → See sfc-scoped-css-child-component-styling

• Styling content added dynamically with v-html → See sfc-scoped-css-dynamic-content

• Optimizing scoped CSS selector performance → See sfc-scoped-css-performance

• Styling content passed through component slots → See sfc-scoped-css-slot-content

• Organizing component template, logic, and styles → See sfc-separation-of-concerns-colocate

• Binding inline styles with property names → See style-binding-camelcase

• Building Tailwind classes with string concatenation → See tailwind-dynamic-class-generation

Plugins

• Global properties not available in setup function → See plugin-prefer-provide-inject-over-global-properties

• Creating a new Vue plugin from scratch → See plugin-structure-install-method

• Preventing collisions between multiple plugins → See plugin-symbol-injection-keys

• Global properties missing TypeScript autocomplete support → See plugin-typescript-type-augmentation

App Configuration

• Need to chain app configuration methods after mount → See mount-return-value

• Vue only controlling specific page sections → See multiple-app-instances

• Migrating dynamic component registration to Vite → See dynamic-component-registration-vite