如何在Javascript中获取另一个数组中某个数组元素的数字出现次数？

Question

我有一个数组：

const myArray1 = [{tags: ['tag-1', 'tag-2']}, {tags: ['tag-1']}, {tags: ['tag-5', 'tag-8']}]

和一个array2：

const myArray2 = [
  {
    tags: [
       "tag-122",
      "tag-1",
      "tag-2",
      "tag-12"
    ]
  },
  {
    tags: [
      "tag-1",
      "tag-10",
      "tag-12"
    ]
  },
  {
    tags: [
      "tag-5"
    ]
  }
];

我想得到一个数组

const resultArray = [{tags: ['tag-1', 'tag-2'], count: 2}, {tags: ['tag-1'], count: 2}, {tags: ['tag-5', 'tag-8'], count: 1}]

对于myArray1中的每个元素，请检查myArray1中是否包含数组标签中的任何元素。 如果包含，查找出现次数

我尝试制作一个myArray2标签数组，然后为myArray1的每个元素在数组中查找

const result = myArray2.reduce((acc, el) => {
  el.tags && el.tags.map(tag => acc.push(tag));
  return acc;
}, []);

Answer 1

我将myArray2转换为Set数组以降低计算复杂度，然后.map the array2并检查.some中是否存在一些被迭代的标签，并用reduce计数出现的次数：

 const myArray1=[{tags:["tag-1","tag-2"]},{tags:["tag-1"]},{tags:["tag-5","tag-8"]}], myArray2=[{tags:["tag-122","tag-1","tag-2","tag-12"]},{tags:["tag-1","tag-10","tag-12"]},{tags:["tag-5"]}]; const arr2Sets = myArray2.map(({ tags }) => new Set(tags)); const resultArray = myArray1.map(({ tags }) => { const count = arr2Sets.reduce( (a, set) => a + tags.some(tag => set.has(tag)), 0 ); return { tags, count }; }); console.log(resultArray);