Performance optimization recommendations

Data Reactivity Optimization

Vue.js's reactivity system is its core feature, but improper usage can lead to performance issues. Avoid using Vue.set or this.$set on large arrays or objects, as this triggers full reactive updates. For static data, using Object.freeze() prevents Vue from adding reactivity:

export default {
  data() {
    return {
      largeList: Object.freeze([...]) // Freeze large static lists
    }
  }
}

The caching mechanism of computed properties effectively reduces redundant calculations. When dependencies remain unchanged, computed properties return cached values directly:

computed: {
  filteredItems() {
    // Recalculates only when the source array changes
    return this.largeList.filter(item => item.isActive)
  }
}

Virtual DOM Optimization

Proper use of the key attribute helps Vue reuse DOM elements more efficiently. For list rendering, avoid using indexes as keys; instead, use unique identifiers:

<template v-for="item in items" :key="item.id">
  <div>{{ item.content }}</div>
</template>

For frequently changing complex components, the v-once directive ensures they render only once:

<div v-once>
  <ComplexComponent :prop="staticValue"/>
</div>

Component Optimization Strategies

Splitting functionality into smaller components improves reusability and rendering efficiency. Avoid handling all logic in the parent component:

// Bad practice: Large component with excessive logic
// Good practice: Split into Presentational and Container components
const SmartList = {
  components: { DumbList },
  template: `
    <DumbList :items="processedItems" @select="handleSelect"/>
  `,
  methods: {
    handleSelect(item) {
      // Business logic handling
    }
  }
}

For infrequently changing child components, use v-show instead of v-if to avoid re-rendering overhead:

<TabContent v-show="activeTab === 'stats'"/>

Event Handling Optimization

Frequently triggered events (e.g., scroll, resize) should use debouncing or throttling. Lodash's _.throttle can be used directly:

import { throttle } from 'lodash'

export default {
  methods: {
    handleScroll: throttle(function() {
      // Scroll handling logic
    }, 200)
  }
}

Clean up custom event listeners promptly to prevent memory leaks:

mounted() {
  this.$on('custom-event', this.handler)
},
beforeDestroy() {
  this.$off('custom-event', this.handler)
}

State Management Optimization

Large Vuex state trees can impact performance. Split state into modules and use getters for derived state calculations:

const store = new Vuex.Store({
  modules: {
    user: userModule,
    products: productsModule
  },
  getters: {
    featuredProducts: state => {
      return state.products.all.filter(p => p.isFeatured)
    }
  }
})

For infrequently changing data, consider using local storage instead of Vuex:

// Initialize data from local storage
data() {
  return {
    preferences: JSON.parse(localStorage.getItem('prefs')) || {}
  }
},
watch: {
  preferences: {
    handler(newVal) {
      localStorage.setItem('prefs', JSON.stringify(newVal))
    },
    deep: true
  }
}

Async Components and Code Splitting

Route-level and component-level code splitting significantly reduces initial load time. Use dynamic import syntax:

const AsyncComponent = () => ({
  component: import('./HeavyComponent.vue'),
  loading: LoadingComponent,
  error: ErrorComponent,
  delay: 200,
  timeout: 3000
})

For Vue Router, configure component-level lazy loading:

const routes = [
  {
    path: '/dashboard',
    component: () => import('./views/Dashboard.vue')
  }
]

Render Function Optimization

In performance-critical scenarios, use render functions instead of templates to avoid the template compilation step:

render(h) {
  return h('div', {
    class: {'active': this.isActive}
  }, [
    h('span', this.text),
    this.showIcon ? h(Icon) : null
  ])
}

For static content, use _c (createStaticVNode) to skip the diff process:

render(h) {
  return h('div', [
    this._c('header', { staticClass: 'app-header' }),
    this.dynamicContent ? h(Content) : null
  ])
}

Third-Party Library Integration

Selectively import Lodash functions instead of the entire library:

import debounce from 'lodash/debounce'

For UI libraries like ElementUI, import components on demand:

import { Button, Select } from 'element-ui'

Vue.component(Button.name, Button)
Vue.component(Select.name, Select)

Production Environment Configuration

Ensure production mode is enabled during builds to remove warnings and dev tools:

// vue.config.js
module.exports = {
  configureWebpack: {
    mode: process.env.NODE_ENV === 'production' 
      ? 'production' 
      : 'development'
  }
}

Enabling Gzip and Brotli compression significantly reduces resource size:

// Use compression-webpack-plugin
const CompressionPlugin = require('compression-webpack-plugin')

module.exports = {
  configureWebpack: {
    plugins: [
      new CompressionPlugin({
        algorithm: 'gzip'
      })
    ]
  }
}

Performance Monitoring and Analysis

Use Vue Devtools' Performance panel to record component rendering times. Add custom performance markers:

mounted() {
  window.performance.mark('component-mounted-start')
  // Initialization logic
  window.performance.mark('component-mounted-end')
  window.performance.measure(
    'Component Mount',
    'component-mounted-start',
    'component-mounted-end'
  )
}

For online monitoring, integrate Web Vitals:

import { getCLS, getFID, getLCP } from 'web-vitals'

getCLS(console.log)
getFID(console.log)
getLCP(console.log)