1---
2name: vue-best-practices
3description: MUST be used for Vue.js tasks. Strongly recommends Composition API with `<script setup>` and TypeScript as the standard approach. Covers Vue 3, SSR, Volar, vue-tsc. Load for any Vue, .vue files, Vue Router, Pinia, or Vite with Vue work. ALWAYS use Composition API unless the project explicitly requires Options API.
4license: MIT
5metadata:
6  author: github.com/vuejs-ai
7  version: "18.0.0"
8---
9 
10# Vue Best Practices Workflow
11 
12Use this skill as an instruction set. Follow the workflow in order unless the user explicitly asks for a different order.
13 
14## Core Principles
15- **Keep state predictable:** one source of truth, derive everything else.
16- **Make data flow explicit:** Props down, Events up for most cases.
17- **Favor small, focused components:** easier to test, reuse, and maintain.
18- **Avoid unnecessary re-renders:** use computed properties and watchers wisely.
19- **Readability counts:** write clear, self-documenting code.
20 
21## 1) Confirm architecture before coding (required)
22 
23- Default stack: Vue 3 + Composition API + `<script setup lang="ts">`.
24- If the project explicitly uses Options API, load `vue-options-api-best-practices` skill if available.
25- If the project explicitly uses JSX, load `vue-jsx-best-practices` skill if available.
26 
27### 1.1 Must-read core references (required)
28 
29- Before implementing any Vue task, make sure to read and apply these core references:
30  - `references/reactivity.md`
31  - `references/sfc.md`
32  - `references/component-data-flow.md`
33  - `references/composables.md`
34- Keep these references in active working context for the entire task, not only when a specific issue appears.
35 
36### 1.2 Plan component boundaries before coding (required)
37 
38Create a brief component map before implementation for any non-trivial feature.
39 
40- Define each component's single responsibility in one sentence.
41- Keep entry/root and route-level view components as composition surfaces by default.
42- Move feature UI and feature logic out of entry/root/view components unless the task is intentionally a tiny single-file demo.
43- Define props/emits contracts for each child component in the map.
44- Prefer a feature folder layout (`components/<feature>/...`, `composables/use<Feature>.ts`) when adding more than one component.
45 
46## 2) Apply essential Vue foundations (required)
47 
48These are essential, must-know foundations. Apply all of them in every Vue task using the core references already loaded in section `1.1`.
49 
50### Reactivity
51 
52- Must-read reference from `1.1`: [reactivity](references/reactivity.md)
53- Keep source state minimal (`ref`/`reactive`), derive everything possible with `computed`.
54- Use watchers for side effects if needed.
55- Avoid recomputing expensive logic in templates.
56 
57### SFC structure and template safety
58 
59- Must-read reference from `1.1`: [sfc](references/sfc.md)
60- Keep SFC sections in this order: `<script>` → `<template>` → `<style>`.
61- Keep SFC responsibilities focused; split large components.
62- Keep templates declarative; move branching/derivation to script.
63- Apply Vue template safety rules (`v-html`, list rendering, conditional rendering choices).
64 
65### Keep components focused
66 
67Split a component when it has **more than one clear responsibility** (e.g. data orchestration + UI, or multiple independent UI sections).
68 
69- Prefer **smaller components + composables** over one “mega component”
70- Move **UI sections** into child components (props in, events out).
71- Move **state/side effects** into composables (`useXxx()`).
72 
73Apply objective split triggers. Split the component if **any** condition is true:
74 
75- It owns both orchestration/state and substantial presentational markup for multiple sections.
76- It has 3+ distinct UI sections (for example: form, filters, list, footer/status).
77- A template block is repeated or could become reusable (item rows, cards, list entries).
78 
79Entry/root and route view rule:
80 
81- Keep entry/root and route view components thin: app shell/layout, provider wiring, and feature composition.
82- Do not place full feature implementations in entry/root/view components when those features contain independent parts.
83- For CRUD/list features (todo, table, catalog, inbox), split at least into:
84  - feature container component
85  - input/form component
86  - list (and/or item) component
87  - footer/actions or filter/status component
88- Allow a single-file implementation only for very small throwaway demos; if chosen, explicitly justify why splitting is unnecessary.
89 
90### Component data flow
91 
92- Must-read reference from `1.1`: [component-data-flow](references/component-data-flow.md)
93- Use props down, events up as the primary model.
94- Use `v-model` only for true two-way component contracts.
95- Use provide/inject only for deep-tree dependencies or shared context.
96- Keep contracts explicit and typed with `defineProps`, `defineEmits`, and `InjectionKey` as needed.
97 
98### Composables
99 
100- Must-read reference from `1.1`: [composables](references/composables.md)
101- Extract logic into composables when it is reused, stateful, or side-effect heavy.
102- Keep composable APIs small, typed, and predictable.
103- Separate feature logic from presentational components.
104 
105## 3) Consider optional features only when requirements call for them
106 
107### 3.1 Standard optional features
108 
109Do not add these by default. Load the matching reference only when the requirement exists.
110 
111- Slots: parent needs to control child content/layout -> [component-slots](references/component-slots.md)
112- Fallthrough attributes: wrapper/base components must forward attrs/events safely -> [component-fallthrough-attrs](references/component-fallthrough-attrs.md)
113- Built-in component `<KeepAlive>` for stateful view caching -> [component-keep-alive](references/component-keep-alive.md)
114- Built-in component `<Teleport>` for overlays/portals -> [component-teleport](references/component-teleport.md)
115- Built-in component `<Suspense>` for async subtree fallback boundaries -> [component-suspense](references/component-suspense.md)
116- Animation-related features: pick the simplest approach that matches the required motion behavior.
117  - Built-in component `<Transition>` for enter/leave effects -> [transition](references/component-transition.md)
118  - Built-in component `<TransitionGroup>` for animated list mutations -> [transition-group](references/component-transition-group.md)
119  - Class-based animation for non-enter/leave effects -> [animation-class-based-technique](references/animation-class-based-technique.md)
120  - State-driven animation for user-input-driven animation -> [animation-state-driven-technique](references/animation-state-driven-technique.md)
121 
122### 3.2 Less-common optional features
123 
124Use these only when there is explicit product or technical need.
125 
126- Directives: behavior is DOM-specific and not a good composable/component fit -> [directives](references/directives.md)
127- Async components: heavy/rarely-used UI should be lazy loaded -> [component-async](references/component-async.md)
128- Render functions only when templates cannot express the requirement -> [render-functions](references/render-functions.md)
129- Plugins when behavior must be installed app-wide -> [plugins](references/plugins.md)
130- State management patterns: app-wide shared state crosses feature boundaries -> [state-management](references/state-management.md)
131 
132## 4) Run performance optimization after behavior is correct
133 
134Performance work is a post-functionality pass. Do not optimize before core behavior is implemented and verified.
135 
136- Large list rendering bottlenecks -> [perf-virtualize-large-lists](references/perf-virtualize-large-lists.md)
137- Static subtrees re-rendering unnecessarily -> [perf-v-once-v-memo-directives](references/perf-v-once-v-memo-directives.md)
138- Over-abstraction in hot list paths -> [perf-avoid-component-abstraction-in-lists](references/perf-avoid-component-abstraction-in-lists.md)
139- Expensive updates triggered too often -> [updated-hook-performance](references/updated-hook-performance.md)
140 
141## 5) Final self-check before finishing
142 
143- Core behavior works and matches requirements.
144- All must-read references were read and applied.
145- Reactivity model is minimal and predictable.
146- SFC structure and template rules are followed.
147- Components are focused and well-factored, splitting when needed.
148- Entry/root and route view components remain composition surfaces unless there is an explicit small-demo exception.
149- Component split decisions are explicit and defensible (responsibility boundaries are clear).
150- Data flow contracts are explicit and typed.
151- Composables are used where reuse/complexity justifies them.
152- Moved state/side effects into composables if applicable
153- Optional features are used only when requirements demand them.
154- Performance changes were applied only after functionality was complete.
155