vue3左右布局，左右两边宽度不固定，可以拖动中间的分割线实现拖动改变宽度

第一个版本如下

<template>
  <div class="split-panel-container">
    <div class="panel-left" :style="{ width: `${leftWidth}%` }">
      <div class="panel-content" v-bind:style="isResizing ? noSelectStyle : {}">
        <slot name="left">
          <div class="default-content">左侧面板内容</div>
        </slot>
      </div>
    </div>
    <div class="resize-handle" @mousedown="startResize">
      <div class="handle-icon"></div>
    </div>
    <div class="panel-right" :style="{ width: `${rightWidth}%` }">
      <div class="panel-content" v-bind:style="isResizing ? noSelectStyle : {}">
        <slot name="right">
          <div class="default-content">右侧面板内容</div>
        </slot>
      </div>
    </div>
  </div>
</template>
<script setup lang="ts">
import { ref, computed, onMounted, onUnmounted } from 'vue'
const props = defineProps({
  defaultLeftWidth: {
    type: Number,
    default: 70
  },
  minLeftWidth: {
    type: Number,
    default: 30
  },
  minRightWidth: {
    type: Number,
    default: 20
  }
})
const leftWidth = ref(props.defaultLeftWidth)
const rightWidth = ref(100 - props.defaultLeftWidth)
const isResizing = ref(false)
// 禁止选择样式
const noSelectStyle = computed(() => ({
  'user-select': 'none',
  '-webkit-user-select': 'none',
  'pointer-events': 'none'
}))
const startResize = (e: MouseEvent) => {
  isResizing.value = true
  document.body.style.cursor = 'col-resize'
  document.addEventListener('mousemove', handleResize)
  document.addEventListener('mouseup', stopResize)
  e.preventDefault() // 阻止默认行为，防止选中内容
}
const handleResize = (e: MouseEvent) => {
  if (!isResizing.value) return
  const container = document.querySelector('.split-panel-container') as HTMLElement
  const containerRect = container.getBoundingClientRect()
  const containerWidth = containerRect.width
  // 计算鼠标在容器中的相对位置百分比
  let mouseX = e.clientX - containerRect.left
  let newLeftWidth = (mouseX / containerWidth) * 100
  // 应用最小宽度限制
  if (newLeftWidth < props.minLeftWidth) newLeftWidth = props.minLeftWidth
  if (newLeftWidth > 100 - props.minRightWidth) newLeftWidth = 100 - props.minRightWidth
  leftWidth.value = newLeftWidth
  rightWidth.value = 100 - newLeftWidth
}
const stopResize = () => {
  isResizing.value = false
  document.body.style.cursor = ''
  document.removeEventListener('mousemove', handleResize)
  document.removeEventListener('mouseup', stopResize)
}
onMounted(() => {
  // 初始化宽度
  leftWidth.value = props.defaultLeftWidth
  rightWidth.value = 100 - props.defaultLeftWidth
})
onUnmounted(() => {
  document.removeEventListener('mousemove', handleResize)
  document.removeEventListener('mouseup', stopResize)
})
</script>
<style scoped lang="scss">
.split-panel-container {
  display: flex;
  width: 100%;
  height: 100%;
  min-height: 300px;
  overflow: hidden;
  .panel-left, .panel-right {
    position: relative;
    overflow: auto;
    transition: width 0.1s ease;
    /* 自定义滚动条 */
    &::-webkit-scrollbar {
      width: 8px;
      height: 8px;
    }
    &::-webkit-scrollbar-track {
      background: transparent;
    }
    &::-webkit-scrollbar-thumb {
      background: rgba(150, 150, 150, 0.5);
      border-radius: 4px;
      transition: background 0.2s;
    }
    &::-webkit-scrollbar-thumb:hover {
      background: rgba(100, 100, 100, 0.7);
    }
  }
  .panel-left {
    /* 关键调整：将左侧面板的右侧padding设置为负数，使内容可以扩展到滚动条区域 */
    padding-right: -8px;
    margin-right: 8px; /* 补偿padding，保持整体宽度不变 */
    /* 让左侧面板的滚动条与分割线重叠 */
    &::-webkit-scrollbar {
      position: absolute;
      right: 0;
      width: 8px; /* 滚动条宽度 */
    }
  }
  .resize-handle {
    position: relative;
    width: 6px;
    background-color: #f0f0f0;
    cursor: col-resize;
    border-left: 1px solid #ddd;
    border-right: 1px solid #ddd;
    z-index: 20; /* 确保分割线在最上层 */
    /* 鼠标悬停和拖动时的样式 */
    &:hover, &:active {
      background-color: #e0e0e0;
    }
    .handle-icon {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      width: 2px;
      height: 30px;
      background-color: #ccc;
      &::before, &::after {
        content: '';
        position: absolute;
        width: 2px;
        height: 30px;
        background-color: #ccc;
      }
      &::before {
        left: -6px;
      }
      &::after {
        left: 6px;
      }
    }
  }
  .panel-content {
    padding: 16px;
    min-height: 100%;
  }
  .default-content {
    padding: 20px;
    background-color: #f9f9f9;
    border-radius: 4px;
    margin: 10px;
  }
}
</style>