分组JavaScript数组

假设我们有一个像这样的JavaScript数组-

const data = [
   {
      "dataId": "1",
      "tableName": "table1",
      "column": "firstHeader",
      "rows": [
         "a","b","c"
      ]
   },
   {
      "dataId": "2",
      "tableName": "table1",
      "column": "secondHeader",
      "rows": [
         "d","e","f",
      ]
   }, {
      "dataId": "3",
      "tableName": "table2",
      "column": "aNewFirstHeader",
      "rows": [
         1,2,3
      ]
   }
];

我们需要在一个这样的数组中编写一个JavaScript函数。该函数应基于原始数组构造一个新的对象分组数组。

分组数组应将单独的唯一“ tableName”对象的数据包含在其自己的对象中。

因此，最终输出应类似于-

const output = [
   {
      "tableName": "table1",
      "column": ["firstHeader", "secondHeader"],
      "rows": [["a","b","c"], ["d","e","f"]]
   },
   {
      "tableName": "table2",
      "column": ["aNewFirstHeader"],
      "rows": [[1,2,3]]
   }
];

示例

const arr = [
   {
      "dataId": "1",
      "tableName": "table1",
      "column": "firstHeader",
      "rows": [ "val","b","c" ]
   },
   {
      "dataId": "2",
      "tableName": "table1",
      "column": "secondHeader",
      "rows": [
         "d","e","f",
      ]
   },
   {
      "dataId": "3",
      "tableName": "table2",
      "column": "aNewFirstHeader",
      "rows": [
         1,2,3
      ]
   }
];
const groupArray = (arr = []) => {
   const res = arr.reduce((obj => (acc, val) => {
      let item = obj.get(val.tableName);
      if (!item) {
         item = {
            tableName: val.tableName, column: [], rows: []
         }
         obj.set(val.tableName, item); acc.push(item);
      };
      item.column.push(val.column); item.rows.push(val.rows);
      return acc;
   })(new Map), []);
   return res;
};
console.log(JSON.stringify(groupArray(arr), undefined, 4));

输出结果

控制台中的输出将是-

[
   {
      "tableName": "table1",
      "column":
      [
         "firstHeader",
         "secondHeader"
      ],
      "rows": [
         [
            "val", "b", "c"
         ],
         [
            "d", "e", "f"
         ]
      ]
   }, {
      "tableName": "table2",
      "column": [
            "aNewFirstHeader"
         ],
         "rows": [
         [
            1, 2, 3
         ]
      ]
   }
]