javascript - 根据javascript中深层嵌套对象中的值过滤数组

Question

我有以下结构的数组:

var topics = [
  {
    "id": 1,
    "name": "topic title 1",
    "sub_categories": [
      {
        "id": 1,
        "name": "category title 1",
        "indicators": [
          {
            "id": 1,
            "name": "indicator 1",
            "sub_category_id": 1
          },
          {
            "id": 7,
            "name": "indicator 7 - foo",
            "sub_category_id": 1
          }
        ]
      },
      {
        "id": 6,
        "name": "category title 6",
        "indicators": [
          {
            "id": 8,
            "name": "indicator 8",
            "sub_category_id": 6
          }
        ]
      }
    ]
  },
  {
    "id": 2,
    "name": "topic title 2",
    "sub_categories": [
      {
        "id": 2,
        "name": "category 2",
        "indicators": [
          {
            "id": 2,
            "name": "indicator 2 - foo",
            "sub_category_id": 2
          }
        ]
      },
      {
        "id": 4,
        "name": "category 4",
        "indicators": [
          {
            "id": 5,
            "name": "indicator 5",
            "sub_category_id": 4
          }
        ]
      }
    ]
  }
];

我需要根据指标数组中名称属性的值获取过滤数组，删除不匹配的指标以及指标为空的主题和子类别。所以对于 foo 的输入，结果将是:

var topics = [
  {
    "id": 1,
    "name": "topic title 1",
    "sub_categories": [
      {
        "id": 1,
        "name": "category title 1",
        "indicators": [
          {
            "id": 7,
            "name": "indicator 7 - foo",
            "sub_category_id": 1
          }
        ]
      }
    ]
  },
  {
    "id": 2,
    "name": "topic title 2",
    "sub_categories": [
      {
        "id": 2,
        "name": "category 2",
        "indicators": [
          {
            "id": 2,
            "name": "indicator 2 - foo",
            "sub_category_id": 2
          }
        ]
      }
    ]
  }
];

我尝试使用基于其他类似 SO 问题的 lodash 方法，但所有示例要么只有一层嵌套，要么在所有级别(即子级)上都具有相同的键。我可以取回新数组或改变现有数组。

Answer 1

下面是一个基于reduce、filter和Object.assign的ES6解决方案:

function filterTree(topics, find) {
    return topics.reduce(function (acc, topic) {
        const sub_categories = topic.sub_categories.reduce(function (acc, cat) {
            const indicators = cat.indicators.filter( ind => ind.name.includes(find) );
            return !indicators.length ? acc
                : acc.concat(Object.assign({}, cat, { indicators }));
        }, []);
        return !sub_categories.length ? acc
            : acc.concat(Object.assign({}, topic, { sub_categories })); 
    }, []);
}

// sample data
const topics = [
  {
    "id": 1,
    "name": "topic title 1",
    "sub_categories": [
      {
        "id": 1,
        "name": "category title 1",
        "indicators": [
          {
            "id": 1,
            "name": "indicator 1",
            "sub_category_id": 1
          },
          {
            "id": 7,
            "name": "indicator 7 - foo",
            "sub_category_id": 1
          }
        ]
      },
      {
        "id": 6,
        "name": "category title 6",
        "indicators": [
          {
            "id": 8,
            "name": "indicator 8",
            "sub_category_id": 6
          }
        ]
      }
    ]
  },
  {
    "id": 2,
    "name": "topic title 2",
    "sub_categories": [
      {
        "id": 2,
        "name": "category 2",
        "indicators": [
          {
            "id": 2,
            "name": "indicator 2 - foo",
            "sub_category_id": 2
          }
        ]
      },
      {
        "id": 4,
        "name": "category 4",
        "indicators": [
          {
            "id": 5,
            "name": "indicator 5",
            "sub_category_id": 4
          }
        ]
      }
    ]
  }
];
// Call the function
var res = filterTree(topics, 'foo');
// Output result
console.log(res);

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