javascript - 普通 JavaScript : Filter nested array by array

Question

考虑以下帖子数组:

posts_array =
[
 {
  id: 1,
  categories: [
   {
    category_id: 1,
    category_name: "one"
   },
   {
    category_id: 2,
    category_name: "two"
   },
 },
 {
  id: 2,
  categories: [
   {
    category_id: 1,
    category_name: "one"
   },
   {
    category_id: 3,
    category_name: "three"
   },
 },
 {
  id: 3,
  categories: [
   {
    category_id: 1,
    category_name: "one"
   },
   {
    category_id: 4,
    category_name: "four"
   },
   {
    category_id: 5,
    category_name: "five"
   },
 }    
]

然后我有一个类别 id 数组，我想用它来过滤上面的数组:

const category_id_array = [1, 4];

我想进行过滤以满足所有条件，即返回 posts_array 中包含两者categories.category_id = 1 和categories.category_id = 4的元素

我尝试过以下内容(使用 .some 函数)，但它返回满足任一条件的元素，即任一categories.category_id = 1或类别。类别 ID = 4

function filterPostsByCategoryIds(category_id_array){
    const filter_categories = category_id_array;
    const custom_filter = d => d.categories.some(c => filter_categories.includes(c.category_id));
    const filtered_posts_array = posts_array.filter(custom_filter);
    return filtered_posts_array;
}

用 .every 交换 .some 根本不会返回任何元素。

如何通过category_id_array过滤posts_array，以便它返回上面示例数组中的最后一个元素，即类别包含category_id_array中的所有category_id？

谢谢，注意安全!

Answer 1

您可以使用.every()在您的category_id_array上并返回true当有.some()时当前.categories内的对象其中有 category_id等于 c 中的当前 id ( category_id_array ) :

const posts_array = [{ id: 1, categories: [{ category_id: 1, category_name: "one" }, { category_id: 2, category_name: "two" } ], }, { id: 2, categories: [{ category_id: 1, category_name: "one" }, { category_id: 3, category_name: "three" } ], }, { id: 3, categories: [{ category_id: 1, category_name: "one" }, { category_id: 4, category_name: "four" }, { category_id: 5, category_name: "five" } ], }];

function filterPostsByCategoryIds(category_id_array) {
  const custom_filter = d => category_id_array.every(c => d.categories.some(o => o.category_id === c));
  const filtered_posts_array = posts_array.filter(custom_filter);
  return filtered_posts_array;
}

const res = filterPostsByCategoryIds([1, 4]);
console.log(res);

您还可以创建一组 category_id对于每个对象，然后使用 .every()与 .has()检查类别数组是否具有 category_id 中的每个 id像这样:

const posts_array = [{ id: 1, categories: [{ category_id: 1, category_name: "one" }, { category_id: 2, category_name: "two" } ], }, { id: 2, categories: [{ category_id: 1, category_name: "one" }, { category_id: 3, category_name: "three" } ], }, { id: 3, categories: [{ category_id: 1, category_name: "one" }, { category_id: 4, category_name: "four" }, { category_id: 5, category_name: "five" } ], }];

function filterPostsByCategoryIds(category_id_array) {
  return posts_array.filter(({categories}) => {
    const cat_ids = new Set(categories.map(({category_id}) => category_id));
    return category_id_array.every(id => cat_ids.has(id));
  });
}

const res = filterPostsByCategoryIds([1, 4]);
console.log(res);