array2tree.ts

/**
 * 把平铺的 array 转成 树
 * 
 * 比如原始数列：
 * [
 *   {id: "13300", parentId: "13300", name: "蔬菜", status: 1},
 *   {id: "13301", parentId: "13301", name: "饮料", status: 1},
 *   {id: "13413", parentId: "13413", name: "青菜类", status: 1},
 *   {id: "13696", parentId: "13696", name: "肉类", status: 1},
 *   {id: "13700", parentId: "13696", name: "鱼肉", status: 1},
 *   {id: "13701", parentId: "13700", name: "黑鱼肉", status: 1}
 * ]
 * 
 * 转变成：
 * [
 *   {id: "13300", parentId: "13300", name: "蔬菜", status: 1},
 *   ...
 *   {id: "13696", parentId: "13696", name: "肉类", status: 1, list: [
 *      {id: "13700", parentId: "13696", name: "鱼肉", status: 1, list: [
 *         {id: "13701", parentId: "13700", name: "黑鱼肉", status: 1}   
 *      ]},
 *   ]}, 
 * ]
 */

interface TreeNode {
  id: string;
  list?: TreeNode[];
  // tslint:disable-next-line:no-any
  [key: string]: any;
}

interface OriginArray {
  id: string;
  parentId?: string;
  // tslint:disable-next-line:no-any
  [key: string]: any;
}

interface Array2Tree {
  (param: Array<OriginArray>): TreeNode[];
}

// 方法1
const traver = (nodes: TreeNode[], array: OriginArray[]) => {
  const nextNodes: TreeNode[] = [];
  const others: OriginArray[] = [];
  let i = 0,
    j = 0;
  while (i < array.length) {
    while (j < nodes.length) {
      if (array[i].parentId === nodes[j].id) {
        nodes[j].list = nodes[j].list || [];
        nodes[j].list!.push(array[i]);
        nextNodes.push(array[i]);
        i++;
        j=0;
        break;
      } else {
        j++;
      }
    }
    if (j === nodes.length) {
      others.push(array[i]);
      i++;
      j=0;
    }
  }
  others.length && nextNodes.length && traver(nextNodes, others);
};

// 方法2
const fn2: Array = (categories) => {
  let result: any = [];
   categories.forEach(item => {
     if (item.parentId === item.id) {
       result.push(item);
     } else {
       const parent = categories.find(it => it.id === item.parentId);
       parent.list ? parent.list.push(item) : parent.list = [item];
     }
   });
   return result;
}


const myFun: Array2Tree = array => {
  const rootNodeArray = array.filter(a => a.id === a.parentId);
  const others = array.filter(a => a.id !== a.parentId);
  traver(rootNodeArray, others);
  return rootNodeArray;
};

export default myFun;