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Question

我有一个对象数组，每个对象都是一个嵌套的整数数组。

[
  {
    "title": "Foo",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      229,
      190
    ]
  },
  {
    "title": "Bar",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      199,
      17
    ]
  },
  {
    "title": "Baz",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      199,
      229
    ]
  }
]

我想要做的是从给定的categoryIds数组中检索一个对象数组 - [229,17]会检索第一个两个项目吗？

尝试使用过滤器，但很难进入类别数组。

var selectedCategories = [229,17];

posts = posts.filter(function(c) {
  return selectedCategories.includes(c.categories);
});

// posts output: []

Answer 1

对于每个帖子，您应该查看其中任何关联类别是否具有selectedCategories中存在的ID。 for ... of回调中的简单posts.filter循环应该可以解决问题：

＆＃13;

var posts = [
  {
    "title": "Foo",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      229,
      190
    ]
  },
  {
    "title": "Bar",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      199,
      17
    ]
  },
  {
    "title": "Baz",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      199,
      230 // Note: I made this 230 to exclude this item
    ]
  }
];

var selectedCategories = [229,17];

posts = posts.filter(function(c) {
  for (let categoryId of c.categories) {
    if (selectedCategories.includes(categoryId)) return true;
  }
  
  return false;
});

console.log(posts);

＆＃13;

Answer 2

您非常接近，但必须针对每个选定的类别（或直到找到匹配项）检查每个类别。您可以使用.some()。

执行此操作

posts = posts.filter(p =>
  p.categories.some(cat => selectedCategories.includes(cat))
);

＆＃13;

var posts = [
  {
    "title": "Foo",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      229,
      190
    ]
  },
  {
    "title": "Bar",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      199,
      17
    ]
  },
  {
    "title": "Baz",
    "date": "2018-02-08T15:55:16",
    "author": 2,
    "categories": [
      199,
      229
    ]
  }
]


var selectedCategories = [229,17];

posts = posts.filter(p =>
  p.categories.some(cat => selectedCategories.includes(cat))
);

console.log(posts)

＆＃13;

Answer 3

您可以创建一个类来重复使用过滤器操作。

let dataArray = [  {    "title": "Foo",    "date": "2018-02-08T15:55:16",    "author": 2,    "categories": [      229,      190    ]  },  {    "title": "Bar",    "date": "2018-02-08T15:55:16",    "author": 2,    "categories": [      199,      17    ]  },  {    "title": "Baz",    "date": "2018-02-08T15:55:16",    "author": 2,    "categories": [      199,      229    ]  }];


function MyFilter(array) {
  this.array = array;
  this.withKey = (key) => {
    this.key = key;
    return this;
  }
  this.withComparator = (fn) => {
    this.comparator = fn;
    return this;
  };

  this.filter = () => this.array.filter(o => this.comparator(o[this.key]));
}

let categoryIds = [229, 17];
let result = new MyFilter(dataArray).withKey('categories').withComparator((catArray) => catArray.some((c) => categoryIds.some((ic) => ic == c))).filter();

console.log(result);

按数组中的值过滤对象数组中的数组

3 个答案:

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