vue+element實現多級菜單(五級菜單，六級菜單等等)

效果圖如下：

實現代碼如下：

	<div class="sidebar">
		<el-menu class="sidebar-el-menu" :default-active="onRoutes" :collapse="collapse" background-color="#324157"
		 text-color="#bfcbd9" active-text-color="#20a0ff" unique-opened router>
			<!-- 第一層 -->
			<template v-for="item in items">
				<!-- 如果第一層有子菜單，則繼續循環 -->
				<template v-if="item.subs">
					<el-submenu :index="item.index" :key="item.index">
						<template slot="title">
							<i :class="item.icon"></i>
							<span slot="title">{{ item.title }}</span>
						</template>
						<!-- 第二層 -->
						<template v-for="subItem in item.subs">
							<!-- 如果第二層有子菜單，則繼續循環 -->
							<template v-if="subItem.subs">
								<el-submenu :index="subItem.index" :key="subItem.index">
									<template slot="title">
										<i :class="item.icon"></i>
										<span slot="title">{{ subItem.title }}</span>
									</template>
									<!-- <el-menu-item v-for="(threeItem,i) in subItem.subs" :key="i" :index="threeItem.index">{{ threeItem.title }}</el-menu-item> -->
									<!-- 第三層 -->
									<template v-for="subItem2 in subItem.subs">
										<!-- 如果第三層有子菜單，則繼續循環 -->
										<template v-if="subItem2.subs">
											<el-submenu :index="subItem2.index" :key="subItem2.index">
												<template slot="title">
													<i :class="item.icon"></i>
													<span slot="title">{{ subItem2.title }}</span>
												</template>
												<!-- <el-menu-item v-for="(fourItem,i) in subItem2.subs" :key="i" :index="fourItem.index">{{ fourItem.title }}</el-menu-item> -->
												<!-- 第四層 -->
												<template v-for="subItem3 in subItem2.subs">
													<!-- 如果第四層有子菜單，則繼續循環 -->
													<template v-if="subItem3.subs">
														<el-submenu :index="subItem3.index" :key="subItem3.index">
															<template slot="title">
																<!-- <i :class="item.icon"></i> -->
																<!-- <span slot="title">{{ subItem2.title }}</span> -->
																{{ subItem3.title }}
															</template>
															<el-menu-item v-for="(fiveItem,i) in subItem3.subs" :key="i" :index="fiveItem.index">{{ fiveItem.title }}</el-menu-item>
														</el-submenu>
													</template>
													<!-- 如果第四層沒有子菜單 -->
													<el-menu-item v-else :index="subItem3.index" :key="subItem3.index">{{ subItem3.title }}</el-menu-item>
												</template>
											</el-submenu>
										</template>
										<!-- 如果第三層沒有子菜單 -->
										<el-menu-item v-else :index="subItem2.index" :key="subItem2.index">{{ subItem2.title }}</el-menu-item>
									</template>
								</el-submenu>
							</template>
							<!-- 如果第二層沒有子菜單 -->
							<el-menu-item v-else :index="subItem.index" :key="subItem.index">{{ subItem.title }}</el-menu-item>
						</template>
					</el-submenu>
				</template>
				<!-- 如果第一層沒有子菜單 -->
				<template v-else>
					<el-menu-item :index="item.index" :key="item.index">
						<i :class="item.icon"></i>
						<span slot="title">{{ item.title }}</span>
					</el-menu-item>
				</template>
			</template>
		</el-menu>
	</div>
</template>

<script>
	import bus from '../common/bus';
	export default {
		data() {
			return {
				collapse: false,
				items: [{
						icon: 'el-icon-lx-home',
						index: 'dashboard',
						title: '系統首頁'
					},
					{
						icon: 'el-icon-lx-cascades',
						index: 'table',
						title: '基礎表格'
					},
					{
						icon: 'el-icon-lx-copy',
						index: 'tabs',
						title: 'tab選項卡'
					},
					{
						icon: 'el-icon-lx-calendar',
						index: '3',
						title: '表單相關',
						subs: [{
								index: 'form',
								title: '基本表單'
							},
							{
								index: '3-2',
								title: '三級菜單',
								subs: [{
										index: 'editor',
										title: '富文本編輯器'
									},
									{
										index: 'markdown',
										title: 'markdown編輯器'
									},
									{
										index: '3-2-1',
										title: '四級菜單',
										subs: [{
											index: 'music',
											title: '網易雲時間'
										},
										{
											index:'math',
											title:'數學時間'
										},{
											index: '3-2-1-1',
											title: '五級菜單',
											subs: [{
												index:'english',
												title:'英語時間'
											}, {
												index:'show',
												title:'展示時間'
											}]
										}]
									}
								]
							},
							{
								index: 'upload',
								title: '文件上傳'
							}
						]
					},
					{
						icon: 'el-icon-lx-emoji',
						index: 'icon',
						title: '自定義圖標'
					},
					{
						icon: 'el-icon-pie-chart',
						index: 'charts',
						title: 'schart圖表'
					},
					{
						icon: 'el-icon-rank',
						index: '6',
						title: '拖拽組件',
						subs: [{
								index: 'drag',
								title: '拖拽列表'
							},
							{
								index: 'dialog',
								title: '拖拽彈框'
							}
						]
					},
					{
						icon: 'el-icon-lx-global',
						index: 'i18n',
						title: '國際化功能'
					},
					{
						icon: 'el-icon-lx-warn',
						index: '7',
						title: '錯誤處理',
						subs: [{
								index: 'permission',
								title: '權限測試'
							},
							{
								index: '404',
								title: '404頁面'
							}
						]
					},
					{
						icon: 'el-icon-lx-redpacket_fill',
						index: '/donate',
						title: '支持作者'
					}
				]
			};
		},
		computed: {
			onRoutes() {
				return this.$route.path.replace('/', '');
			}
		},
		// created() {
			// // 通過 Event Bus 進行組件間通信，來折疊側邊欄,這里接收的是header.vue那邊的數據collapse
			// bus.$on('collapse', msg => {
				// console.log("sidebar.vue",msg);
				// this.collapse = msg;
				// // 這里是向home.vue發送數據collapse-content
				// bus.$emit('collapse-content', msg);
			// });
		// }
	};
</script>

<style scoped>
	.sidebar {
		display: block;
		position: absolute;
		left: 0;
		top: 70px;
		bottom: 0;
		overflow-y: scroll;
	}

	.sidebar::-webkit-scrollbar {
		width: 0;
	}

	.sidebar-el-menu:not(.el-menu--collapse) {
		width: 250px;
	}

	.sidebar>ul {
		height: 100%;
	}
</style>```