在JavaScirpt中，如何过滤两个数组中相同字段的元素并返回一个新的二维数组

Question

This is an example：

I want to regroup arry2 according to the fields in arry1

var arry1 = [
  {id: 1, parentId: 0, name: "phone"},
  {id: 2, parentId: 1, name: "nick"}
];

var arry2 = [
  {id: 7, parentId: 0, name: "phone_item1"},
  {id: 8, parentId: 1, name: "phone_item2"},
  {id: 9, parentId: 0, name: "nick_item1"},
  {id: 10, parentId: 1, name: "nick_item2"}
];


let newArrys = arry1.filter((item)=>{
   return leve_two.indexOf(arry2.parentId) == -1
})

I want to return a two-dimensional array:

[[
  {id: 7, parentId: 0, name: "phone_item1"},
  {id: 9, parentId: 0, name: "nick_item1"}
],[
  {id: 8, parentId: 1, name: "phone_item2"},
  {id: 10, parentId: 1, name: "nick_item2"}
]]

I tried Array.filter and so on.

Can you help me?

Answer 1

You can use filter() method along-with Object.values() to get the desired output:

 const arr1 = [ {id: 1, parentId: 0, name: "phone", level: 0, productCount: 0}, {id: 2, parentId: 1, name: "nick", level: 0, productCount: 0} ]; const arr2 = [ {id: 7, parentId: 0, name: "phone_item1", level: 1, productCount: 0}, {id: 8, parentId: 1, name: "phone_item2", level: 1, productCount: 0}, {id: 9, parentId: 0, name: "nick_item1", level: 1, productCount: 0}, {id: 10, parentId: 1, name: "nick_item2", level: 1, productCount: 0} ]; const filterIds = arr1.map(({ parentId }) => parentId); const arr3 = Object.values(arr2.reduce((r, c) => { r[c.parentId] = r[c.parentId] || []; r[c.parentId].push(c); return r; }, {})); console.log(arr3);

 .as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

It looks just like grouping arry2 by parentId and arry1 looks useless 🤔

Use some lib for this. For example Ramda way:

const result = R.pipe(
  R.groupBy(R.prop("parentId")),
  R.toPairs,
  R.map(R.last)
)(arry2)