鼠标悬浮在树组件节点上展示当前节点名称的三种实现方式

<el-tree v-if="showCheck" ref="treeRef" :data="treeData" :props="keyProps" :filter-node-method="filterAction" :default-expand-all="expandFlag">
	<template v-slot:default="{ node, data }">
		<span class="custom-tree-node tree-node" :data-label="node.label">
			<el-checkbox-group v-if="!data[keyProps.children]" v-model="checkValue">
				<el-checkbox :label="data[keyProps.value]" :disabled="data.disabled" @change="flag => onCheck(flag, data)">
					{{ node.label }}
				</el-checkbox>
			</el-checkbox-group>
			<span v-else>
				{{ node.label }}
			</span>
		</span>
	</template>
</el-tree>

:deep(.el-tree) {
	.el-tree-node__content {
		position: relative;
	}
	.tree-node:hover::before {
		content: attr(data-label); /* 设置节点名称内容 */
		position: absolute;
		top: 26px; /* 调整弹出框位置 */
		left: 40px;
		background-color: #fff; /* 弹出框背景色 */
		padding: 4px 8px;
		border: 1px solid #ccc; /* 弹出框边框样式 */
		border-radius: 4px;
		z-index: 999;
	}
}

<el-tree v-if="showCheck" ref="treeRef" :data="treeData" :props="keyProps" :filter-node-method="filterAction" :default-expand-all="expandFlag">
	<template v-slot:default="{ node, data }">
		<span class="custom-tree-node">
			<el-checkbox-group v-if="!data[keyProps.children]" v-model="checkValue">
				<el-checkbox :label="data[keyProps.value]" :disabled="data.disabled" @change="flag => onCheck(flag, data)" :title="node.label">
					{{ node.label }}
				</el-checkbox>
			</el-checkbox-group>
			<span v-else>
				{{ node.label }}
			</span>
		</span>
	</template>
</el-tree>

<el-tree v-if="showCheck" ref="treeRef" :data="treeData" :props="keyProps" :filter-node-method="filterAction" :default-expand-all="expandFlag">
	<template v-slot:default="{ node, data }">
		<span class="custom-tree-node">
			<el-checkbox-group v-if="!data[keyProps.children]" v-model="checkValue">
				<el-checkbox :label="data[keyProps.value]" :disabled="data.disabled" @change="flag => onCheck(flag, data)">
					<el-tooltip class="item" effect="dark" :content="node.label" placement="bottom-start" show-after="300">
						<template>
							<span>{{ node.label }}</span>
						</template>
					</el-tooltip>
				</el-checkbox>
			</el-checkbox-group>
			<span v-else>
				<el-tooltip class="item" effect="dark" :content="node.label" placement="bottom-start" show-after="300">
					<template>
						<span>{{ node.label }}</span>
					</template>
				</el-tooltip>
			</span>
		</span>
	</template>
</el-tree>