` let list = [ { id: '1', title: '节点1', parentId: '', }, { id: '1-1', title: '节点1-1', parentId: '1' }, { id: '1-2', title: '节点1-2', parentId: '1' }, { id: '2', title: '节点2', parentId: '' }, { id: '2-1', title: '节点2-1', parentId: '2' } ] console.log(list)
function convert(list){
const result = []
let map = list.reduce((pre,cur) => {
pre[cur.id] = cur
return pre
},{})
for (let item of list ){
if(item.parentId == ''){
result.push(item)
}
if(item.parentId in map){
const parent = map[item.parentId]
parent.children =parent.children || []
parent.children.push(item)
}
}
return result
}
let res = convert(list)
console.log(res)
function flat(list){
return list.reduce((pre,cur) => {
const {id ,title, parentId,children=[] } =cur
return pre.concat([{id,title,parentId}],flat(children))
},[])
}
console.log( flat(res))
`
