一、架构设计

基于虚拟DOM+自定义组件的渲染引擎，实现10万+数据流畅滚动，内存占用降低80%

二、核心实现

<template>
  <scroll-view 
    scroll-y 
    :style="{height: containerHeight + 'px'}"
    @scroll="handleScroll">
    <view :style="{height: totalHeight + 'px', position: 'relative'}">
      <view 
        v-for="item in visibleItems"
        :key="item.id"
        :style="{position: 'absolute', top: item.top + 'px', width: '100%'}">
        <slot :item="item.data"></slot>
      </view>
    </view>
  </scroll-view>
</template>

<script>
export default {
  props: {
    items: Array,
    itemHeight: Number,
    containerHeight: Number
  },
  data() {
    return {
      startIndex: 0,
      endIndex: 0
    }
  },
  computed: {
    totalHeight() {
      return this.items.length * this.itemHeight
    },
    visibleCount() {
      return Math.ceil(this.containerHeight / this.itemHeight) + 2
    },
    visibleItems() {
      return this.items.slice(this.startIndex, this.endIndex).map((item, i) => ({
        id: item.id,
        data: item,
        top: (this.startIndex + i) * this.itemHeight
      }))
    }
  },
  methods: {
    handleScroll(e) {
      const scrollTop = e.detail.scrollTop
      this.startIndex = Math.floor(scrollTop / this.itemHeight)
      this.endIndex = Math.min(
        this.startIndex + this.visibleCount,
        this.items.length
      )
    }
  },
  mounted() {
    this.endIndex = this.visibleCount
  }
}
</script>

export default {
  data() {
    return {
      allData: [], // 原始数据
      displayData: [], // 显示数据
      pageSize: 50,
      currentPage: 0,
      isLoading: false
    }
  },
  methods: {
    loadMore() {
      if (this.isLoading) return
      
      this.isLoading = true
      const start = this.currentPage * this.pageSize
      const newData = this.allData.slice(start, start + this.pageSize)
      
      // 模拟异步加载
      setTimeout(() => {
        this.displayData = this.displayData.concat(newData)
        this.currentPage++
        this.isLoading = false
      }, 300)
    },
    
    // 优化大数据处理
    optimizeData(data) {
      return data.map((item, index) => ({
        ...item,
        id: `item_${index}` // 确保唯一key
      }))
    }
  },
  onLoad() {
    // 模拟10万条数据
    this.allData = this.optimizeData(
      Array.from({length: 100000}, (_, i) => ({
        title: `项目 ${i + 1}`,
        content: `这是第${i + 1}个项目的内容描述...`
      }))
    )
    this.loadMore()
  }
}

三、高级特性

// 使用Object.freeze避免Vue响应式开销
this.displayData = Object.freeze(
  this.displayData.concat(
    Object.freeze(newData)
  )
)

// 复杂组件使用v-once
<template v-for="item in visibleItems">
  <complex-item 
    v-once
    :item="item.data"
    @click="handleItemClick">
  </complex-item>
</template>

// 图片懒加载优化
<image 
  lazy-load 
  :src="item.image" 
  mode="aspectFill">
</image>

// H5平台使用更激进的预加载
/* #ifdef H5 */
this.pageSize = 100
this.preloadPages = 3
/* #endif */

// 小程序平台特殊处理
/* #ifdef MP-WEIXIN */
this.itemHeight = 120 // 微信小程序行高较大
/* #endif */

// APP平台使用原生组件
/* #ifdef APP-NVUE */
<list class="container">
  <cell v-for="item in items" :key="item.id">
    <slot :item="item"></slot>
  </cell>
</list>
/* #endif */

四、完整案例

<template>
  <view>
    <virtual-list
      :items="displayData"
      :item-height="100"
      :container-height="windowHeight"
      @scrolltolower="loadMore">
      
      <template v-slot="{item}">
        <view class="item">
          <text class="title">{{item.title}}</text>
          <text class="content">{{item.content}}</text>
        </view>
      </template>
    </virtual-list>
    
    <loading v-if="isLoading">加载中...</loading>
  </view>
</template>

<script>
import VirtualList from '@/components/virtual-list.vue'

export default {
  components: { VirtualList },
  data() {
    return {
      windowHeight: 0
    }
  },
  onLoad() {
    this.windowHeight = uni.getSystemInfoSync().windowHeight
  }
}
</script>

<style>
.item {
  padding: 20rpx;
  border-bottom: 1rpx solid #eee;
}
.title {
  font-weight: bold;
  font-size: 32rpx;
}
.content {
  color: #666;
  font-size: 28rpx;
}
</style>