Using stores in components in Vue - Performance & Optimization

Performance: Using stores in components

MEDIUM IMPACT

Using stores in Vue components affects how state updates trigger component re-renders and how efficiently data flows through the app.

Accessing store state in multiple components causing unnecessary re-renders

Vue

import { useStore } from 'vuex';
import { computed } from 'vue';
export default {
  setup() {
    const store = useStore();
    const count = computed(() => store.getters['getCount']);
    return { count };
  }
}

Using getters or selective computed properties limits re-renders to only when relevant state changes.

📈 Performance Gainreduces unnecessary re-renders, improving input responsiveness

Accessing store state in multiple components causing unnecessary re-renders

Vue

import { useStore } from 'vuex';
import { computed } from 'vue';
export default {
  setup() {
    const store = useStore();
    const count = computed(() => store.state.count);
    return { count };
  }
}

Directly using the entire store state or large objects causes all dependent components to re-render on any state change, even unrelated ones.

📉 Performance Costtriggers re-render for all components using store state on any mutation

Performance Comparison

Pattern	DOM Operations	Reflows	Paint Cost	Verdict
Direct store state access in many components	High (many reactive dependencies)	High (many re-renders)	High (many paints)	[X] Bad
Using selective getters and mutations	Low (minimal reactive dependencies)	Low (targeted re-renders)	Low (fewer paints)	[OK] Good

Rendering Pipeline

When a store state changes, Vue tracks dependencies and schedules component re-renders. Efficient store usage minimizes the number of components that re-render and reduces layout recalculations.

→Dependency Tracking

→Component Re-render

→Layout

→Paint

⚠️ BottleneckComponent Re-render stage is most expensive due to unnecessary updates.

Core Web Vital Affected

INP

Using stores in Vue components affects how state updates trigger component re-renders and how efficiently data flows through the app.

Optimization Tips

1Use computed getters to access only needed store state in components.

2Always update store state via mutations to ensure proper tracking.

3Avoid accessing large or entire store state directly in multiple components.

Performance Quiz - 3 Questions

What is a performance risk when directly accessing large store state objects in many components?

A Components never update

B Store state becomes immutable

C All components re-render on any store change

D Store size increases

DevTools: Performance

How to check: Record a performance profile while interacting with components that use the store. Look for frequent component re-renders and long scripting times.

What to look for: Check the flame chart for repeated renders of components on unrelated store changes indicating inefficient store usage.