数组扁平结构与树状tree结构转化

话不多说，tree数据结构如图：

一、tree结构扁平化

        function flatFuc(arr) {
            return arr.reduce((pre, cur) => {
                if (cur.children) {
                    let curArr = JSON.parse(JSON.stringify(cur.children))
                    delete cur.children
                    pre.push(cur)
                    pre.push(...flatFuc(curArr))
                } else {
                    pre.push(cur)
                }
                return pre
            }, [])
        }
        const flatArr = flatFuc(this.areasOptions);
        console.log(123, flatArr)

结果如图：

 

二、扁平结构转为tree结构

将上图扁平结构转为tree结构

方法一、

        function treeFuc(list, root) {
            return root.reduce((pre, cur, i) => {
                const arr = list.filter(v => v.parentId === cur.value)
                if (arr.length) {
                    pre[i].children = treeFuc(flatArr, arr)
                }
                return pre
            }, root)
        }
        const treeData = treeFuc(flatArr, flatArr.filter(v => v.parentId === '0'))
        console.log(789, treeData)

方法二、

        function buildTree1(list, root) {
            root.forEach((item, index) => {
                const arr = list.filter(v => v.parentId === root[index].value)
                if (arr.length) {
                    item.children = buildTree1(flatArr, arr)
                }
            })
            return root
        }
        const treeData1 = buildTree1(flatArr, flatArr.filter(v => v.parentId === '0'))
        console.log('000', treeData1)

结果如图：

 更多方法请看：https://www.cnblogs.com/younghxp/p/14307918.html