JavaScript 如何通过两个不同的 arrays 对象并有条件地返回一个数组

Question

hello I need help creating the newProducts in the following example array dynamically without knowing what's in the other two arrays https://jsfiddle.net/od4267fv/ more explanation:

I would like to check

products = [
  {
    id: 1,
    name: 'product 1' ,
    liked:  false
  },
{
    id: 2,
    name: 'product 2' ,
    liked:  false
  },
  {
    id: 3,
    name: 'product 3' ,
    liked:  false
  },
  {
    id: 4,
    name: 'product 4' ,
    liked:  false
  },
  {
    id: 5,
    name: 'product 5' ,
    liked:  false
  },

]
likedProducts = [
   {
    id: 1,
    name: 'product 1' ,
    liked:  true
  },
{
    id: 2,
    name: 'product 2' ,
    liked:  true
  },
  {
    id: 3,
    name: 'product 3' ,
    liked:  true
  },

]
if proucts[product].id === likedProducts[product].id
newProducts.push(likedProducts[product])
else
newProducts.push(proucts[product])

please recommend suitable ways to do it

Answer 1

Try this

const allProducts = products.filter(n => likedProducts.find(n2 => n.id == n2.id));

Answer 2

You can do the following using map() and findIndex() ,

 products = [ { id: 1, name: 'product 1', liked: false }, { id: 2, name: 'product 2', liked: false }, { id: 3, name: 'product 3', liked: false }, { id: 4, name: 'product 4', liked: false }, { id: 5, name: 'product 5', liked: false }, ] likedProducts = [ { id: 1, name: 'product 1', liked: true }, { id: 2, name: 'product 2', liked: true }, { id: 3, name: 'product 3', liked: true }, ] newProducts = products.map(item => { let index = likedProducts.findIndex(likedProduct => likedProduct.id === item.id); if(index > -1) { return likedProducts[index]; } return item; }) console.log(newProducts);

Answer 3

This is the way to iterate over 2 array and update value upon some certain condition.

 const updatedProduct = proucts.map((row, indexOfRows) => { for (let index = 0; index < likedProducts.length; index++) { if (likedProducts[index].id === row.id) { return likedProducts[index]; } } return row; });

Answer 4

You can do a single iteration over each of the arrays. First index all products by their id, then iterate over the liked products and overwrite the indexed items. This way, it doesn't matter how many items each array has, nor do you need to do constant lookups into at least one of the arrays.

 const products = [{id: 1,name: 'product 1',liked: false},{id: 2,name: 'product 2',liked: false},{id: 3,name: 'product 3',liked: false},{id: 4,name: 'product 4',liked: false},{id: 5,name: 'product 5',liked: false},]; const likedProducts = [{id: 1,name: 'product 1',liked: true},{id: 2,name: 'product 2',liked: true},{id: 3,name: 'product 3',liked: true},]; const index = new Map(); //index all products for (let item of products) { index.set(item.id, item); } //overwrite anything that is liked for (let likedItem of likedProducts) { if (index.has(likedItem.id)) { index.set(likedItem.id, likedItem); } } //construct a new array from the values const result = Array.from(index.values()); console.log(result);