vue-ops

Vue Operations

Comprehensive Vue 3 reference covering Composition API, Pinia, Vue Router, Nuxt 4, and testing — production patterns with TypeScript throughout.

Vue 3 / Nuxt 4 ecosystem facts verified as of 2026-07-05.

Reactivity Decision Tree

What data do I need to make reactive?
│
├─ A single primitive (string, number, boolean)?
│   └─ ref()
│       const count = ref(0)
│       const name = ref('')
│
├─ A plain object or array with deep reactivity?
│   ├─ Will I destructure it or pass properties individually?
│   │   └─ reactive() — but use toRefs() when destructuring
│   └─ Will I replace the whole object at once?
│       └─ ref() — ref.value = newObject
│
├─ Derived/computed state from other reactive sources?
│   └─ computed()
│       const doubled = computed(() => count.value * 2)
│
├─ A large object where only top-level keys change?
│   └─ shallowRef() or shallowReactive()
│       const state = shallowRef({ nested: { big: 'data' } })
│
├─ Side effects that should run when dependencies change?
│   ├─ Don't need to know old value, auto-tracks dependencies?
│   │   └─ watchEffect(() => { ... })
│   └─ Need old/new values, explicit sources, or lazy execution?
│       └─ watch(source, (newVal, oldVal) => { ... })
│
└─ Data that should NOT be reactive (raw DOM, third-party instances)?
    └─ markRaw(obj) or shallowRef(obj)

Component Communication Decision Tree

How far does data need to travel?
│
├─ Parent → direct child?
│   └─ props (defineProps)
│       Direct, explicit, type-safe
│
├─ Child → parent (user action / data update)?
│   └─ emit (defineEmits)
│       defineEmits<{ change: [value: string] }>()
│
├─ Parent ↔ child bidirectional binding?
│   └─ v-model via defineModel() (Vue 3.4+)
│       const model = defineModel<string>()
│
├─ Ancestor → deep descendant (prop drilling problem)?
│   └─ provide / inject
│       Use InjectionKey<T> for type safety
│
├─ Siblings or unrelated components?
│   ├─ Simple/few shared values?
│   │   └─ provide / inject from a common ancestor
│   └─ Complex shared state or cross-tree communication?
│       └─ Pinia store
│
├─ Truly global state (user session, cart, preferences)?
│   └─ Pinia store
│       defineStore with setup syntax
│
└─ One-time events between distant components (rare)?
    └─ Pinia action + watch, or mitt event bus
        Avoid: Vue removed $emit on root in Vue 3