117 lines
3.5 KiB
JavaScript
117 lines
3.5 KiB
JavaScript
function buildMenu(menu, menuList, menuIds, visited) {
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visited = visited || new Set()
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let nextLayer = []
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for (let i = menu.length - 1; i > -1; i--) {
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const currentMenu = menu[i]
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if (visited.has(currentMenu.menu_id)) continue
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visited.add(currentMenu.menu_id)
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const subMenu = menuList.filter(item => {
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if (item.parent_id === currentMenu.menu_id) {
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if (visited.has(item.menu_id)) return false
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menuIds.push(item.menu_id)
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return true
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}
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})
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nextLayer = nextLayer.concat(subMenu)
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currentMenu.children = subMenu
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}
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if (nextLayer.length) {
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buildMenu(nextLayer, menuList, menuIds, visited)
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}
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}
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function getParentIds(menuItem, menuList) {
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const parentArr = []
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const visited = new Set()
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let currentItem = menuItem
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while (currentItem && currentItem.parent_id) {
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if (visited.has(currentItem.parent_id)) {
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// B7-1: 数据成环（A→B、B→A）时立即返回已收集链，不再死循环
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parentArr.push(currentItem.parent_id)
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break
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}
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visited.add(currentItem.parent_id)
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parentArr.push(currentItem.parent_id)
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currentItem = menuList.find(item => item.menu_id === currentItem.parent_id)
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}
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return parentArr
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}
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// B7-1: 判断把 menuId 的 parent 改为 newParentId 是否会成环
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function wouldCreateCycle(menuList, menuId, newParentId) {
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if (!newParentId) return false
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if (newParentId === menuId) return true
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const visited = new Set()
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let current = newParentId
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while (current) {
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if (current === menuId) return true
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if (visited.has(current)) return true
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visited.add(current)
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const item = menuList.find(m => m.menu_id === current)
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current = item && item.parent_id
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}
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return false
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}
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function buildMenus(menuList, trim = true) {
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// B7-1: sort 比较器不再每次重算 getParentIds —— 记忆化一次算完（链式 O(n)）
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const byId = new Map()
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for (const item of menuList) byId.set(item.menu_id, item)
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const parentMap = new Map()
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function ancestors(id) {
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if (parentMap.has(id)) return parentMap.get(id)
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const chain = []
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const visited = new Set()
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let cur = byId.get(id)
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while (cur && cur.parent_id) {
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if (visited.has(cur.parent_id)) { chain.push(cur.parent_id); break }
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visited.add(cur.parent_id)
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chain.push(cur.parent_id)
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if (parentMap.has(cur.parent_id)) { chain.push(...parentMap.get(cur.parent_id)); break }
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cur = byId.get(cur.parent_id)
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}
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parentMap.set(id, chain)
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return chain
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}
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for (const item of menuList) ancestors(item.menu_id)
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// 保证父子级顺序
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menuList = menuList.sort(function(a, b) {
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const parentIdsA = parentMap.get(a.menu_id) || []
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const parentIdsB = parentMap.get(b.menu_id) || []
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if (parentIdsA.includes(b.menu_id)) {
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return 1
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}
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return parentIdsA.length - parentIdsB.length || a.sort - b.sort
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})
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// 删除无subMenu且非子节点的菜单项
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if (trim) {
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for (let i = menuList.length - 1; i > -1; i--) {
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const currentMenu = menuList[i]
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const subMenu = menuList.filter(subMenuItem => subMenuItem.parent_id === currentMenu.menu_id)
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if (!currentMenu.isLeafNode && !subMenu.length) {
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menuList.splice(i, 1)
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}
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}
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}
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const menuIds = []
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const menu = menuList.filter(item => {
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if (!item.parent_id) {
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menuIds.push(item.menu_id)
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return true
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}
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})
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buildMenu(menu, menuList, menuIds, new Set())
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// 包含所有无效菜单
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if (!trim && menuIds.length !== menuList.length) {
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menu.push(...menuList.filter(item => !menuIds.includes(item.menu_id)))
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}
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return menu
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}
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export {
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buildMenu,
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buildMenus,
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getParentIds,
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wouldCreateCycle
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}
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