一、背景

若依前后端分离的版本，新版本中优化了菜单名称过长悬停显示标题，但是是悬浮所有长度大于5的标题。可以查看提交记录：https://gitee.com/y_project/RuoYi-Cloud/commit/99932d91c0144da9f34f5bb05683cc0b86303217
但是我希望是只悬浮菜单名称过长的菜单，所以做了改进。
因为菜单使用的是elementUI的el-menu做的，所以都可以做参考。

二、效果

鼠标放到展示省略号的菜单栏上会展示气泡，没省略号的则不展示气泡。
实现后效果如下图↓↓↓

三、代码修改

1、如果使用的是最新版本的ruoyi，可以先去掉路径src/layout/components/Sidebar/Item.vue文件中做的标题长度大于5的判断

2、修改路径src\layout\components\Sidebar\SidebarItem.vue代码，新增部分我做了注释：

<template>
  <div v-if="!item.hidden">
    <template
      v-if="
        hasOneShowingChild(item.children, item) &&
        (!onlyOneChild.children || onlyOneChild.noShowingChildren) &&
        !item.alwaysShow
      "
    >
    <!-- 新增气泡部分 -->
      <app-link
        v-if="onlyOneChild.meta"
        :to="resolvePath(onlyOneChild.path, onlyOneChild.query)"
      >
        <el-tooltip
          class="item"
          effect="dark"
          :disabled="isShowTooltip"
          :content="onlyOneChild.meta.title"
          placement="right-start"
        >
          <el-menu-item
            :index="resolvePath(onlyOneChild.path)"
            :class="{ 'submenu-title-noDropdown': !isNest }"
            @mouseenter.native="onMouseOver($event)"
          >
            <span v-if="onlyOneChild.meta"
              ><item
                :icon="onlyOneChild.meta.icon || (item.meta && item.meta.icon)"
                :title="onlyOneChild.meta.title"
            /></span>
          </el-menu-item>
        </el-tooltip>
      </app-link>
    </template>

    <el-submenu
      v-else
      ref="subMenu"
      :index="resolvePath(item.path)"
      popper-append-to-body
    >
      <template slot="title">
        <item
          v-if="item.meta"
          :icon="item.meta && item.meta.icon"
          :title="item.meta.title"
        />
      </template>
      <sidebar-item
        v-for="child in item.children"
        :key="child.path"
        :is-nest="true"
        :item="child"
        :base-path="resolvePath(child.path)"
        class="nest-menu"
      />
    </el-submenu>
  </div>
</template>

<script>
import path from "path";
import { isExternal } from "@/utils/validate";
import Item from "./Item";
import AppLink from "./Link";
import FixiOSBug from "./FixiOSBug";

export default {
  name: "SidebarItem",
  components: { Item, AppLink },
  mixins: [FixiOSBug],
  props: {
    // route object
    item: {
      type: Object,
      required: true,
    },
    isNest: {
      type: Boolean,
      default: false,
    },
    basePath: {
      type: String,
      default: "",
    },
  },
  data() {
    this.onlyOneChild = null;
    // 新增是否显示气泡判定
    return {
      isShowTooltip: false,
    };
  },
  methods: {
    hasOneShowingChild(children = [], parent) {
      if (!children) {
        children = [];
      }
      const showingChildren = children.filter((item) => {
        if (item.hidden) {
          return false;
        } else {
          // Temp set(will be used if only has one showing child)
          this.onlyOneChild = item;
          return true;
        }
      });

      // When there is only one child router, the child router is displayed by default
      if (showingChildren.length === 1) {
        return true;
      }

      // Show parent if there are no child router to display
      if (showingChildren.length === 0) {
        this.onlyOneChild = { ...parent, path: "", noShowingChildren: true };
        return true;
      }

      return false;
    },
    resolvePath(routePath, routeQuery) {
      if (isExternal(routePath)) {
        return routePath;
      }
      if (isExternal(this.basePath)) {
        return this.basePath;
      }
      if (routeQuery) {
        let query = JSON.parse(routeQuery);
        return { path: path.resolve(this.basePath, routePath), query: query };
      }
      return path.resolve(this.basePath, routePath);
    },
    // 新增当显示省略号是才显示气泡方法
    onMouseOver(e) {
      const target = e.target;
      const computedStyle = window.getComputedStyle(target);
      this.isShowTooltip =
        this.$el.querySelector("span")?.offsetWidth <=
        parseFloat(computedStyle?.width) -
          parseFloat(computedStyle?.paddingLeft) -
          parseFloat(computedStyle?.paddingRight);
    },
  },
};
</script>