How to create a vanilla groupBy so that it returns an array of objects that have a title?-CodePudding

There is a function that groups an array of objects by key. For example an array:

     data: [
        {
          CS_NAME: "AAA",
          IS_MAIN: "Y",
          WEBSITE_CREATE_DATE: "2021-06-01T15:50:37.687",
        },
        {
          CS_NAME: "AAA",
          IS_MAIN: "N",
          WEBSITE_CREATE_DATE: "2021-08-03T12:02:58.07",
        },
        {
          CS_NAME: "BBB",
          IS_MAIN: "Y",
          WEBSITE_CREATE_DATE: "2021-08-03T12:02:58.07",
        },
        {
          CS_NAME: "BBB",
          IS_MAIN: "N",
          WEBSITE_CREATE_DATE: "2019-01-26T00:00:00",
        },
        {
          CS_NAME: "CCC",
          IS_MAIN: "Y",
          WEBSITE_CREATE_DATE: "2019-01-26T00:00:00",
        },
      ]

Function groupBy:

    groupBy(input, key) {
    
              return input.reduce((acc, currentValue) => {
                let groupKey = currentValue[key];
                if (!acc[groupKey]) {
                  acc[groupKey] = [];
                }
                acc[groupKey].push(currentValue);
                return acc;
              }, {});
            },
        
        let obj = groupBy(data, "CS_NAME");

How to change this function so that it returns an array of objects, each of which will have two fields:

    {
       title: "CS_NAME" // the key by which objects were grouped or any other property
       content: {obj} // the whole object
    }

For example, the output should be like this:

    {
      title: "AAA",
      content: [
        {
          CS_NAME: "AAA",
          IS_MAIN: "Y",
          WEBSITE_CREATE_DATE: "2021-06-01T15:50:37.687",
        },
    
        {
          CS_NAME: "AAA",
          IS_MAIN: "N",
          WEBSITE_CREATE_DATE: "2021-08-03T12:02:58.07",
        },
      ],
    }

CodePudding user response：

You can update your groupBy function as below to get the desired output. Get the output of the current output with Object.entries and map to an array again.

const data = [ { CS_NAME: "AAA", IS_MAIN: "Y", WEBSITE_CREATE_DATE: "2021-06-01T15:50:37.687", }, { CS_NAME: "AAA", IS_MAIN: "N", WEBSITE_CREATE_DATE: "2021-08-03T12:02:58.07", }, { CS_NAME: "BBB", IS_MAIN: "Y", WEBSITE_CREATE_DATE: "2021-08-03T12:02:58.07", }, { CS_NAME: "BBB", IS_MAIN: "N", WEBSITE_CREATE_DATE: "2019-01-26T00:00:00", }, { CS_NAME: "CCC", IS_MAIN: "Y", WEBSITE_CREATE_DATE: "2019-01-26T00:00:00", }, ];

const groupBy = (input, key) => {
  return Object.entries(
    input.reduce((acc, currentValue) => {
      let groupKey = currentValue[key];
      if (!acc[groupKey]) {
        acc[groupKey] = [];
      }
      acc[groupKey].push(currentValue);
      return acc;
    }, {})
  ).map(([title, content]) => ({ title, content }));
};

const obj = groupBy(data, "CS_NAME");

console.log(obj);

CodePudding user response：

You could map the groupd values and add some properties.

const
    groupBy = (input, key) => input.reduce((acc, currentValue) => {
        (acc[currentValue[key]] ??= []).push(currentValue);
        return acc;
    }, {}),
    data = [{ CS_NAME: "AAA", IS_MAIN: "Y", WEBSITE_CREATE_DATE: "2021-06-01T15:50:37.687" }, { CS_NAME: "AAA", IS_MAIN: "N", WEBSITE_CREATE_DATE: "2021-08-03T12:02:58.07" }, { CS_NAME: "BBB", IS_MAIN: "Y", WEBSITE_CREATE_DATE: "2021-08-03T12:02:58.07" }, { CS_NAME: "BBB", IS_MAIN: "N", WEBSITE_CREATE_DATE: "2019-01-26T00:00:00" }, { CS_NAME: "CCC", IS_MAIN: "Y", WEBSITE_CREATE_DATE: "2019-01-26T00:00:00" }],
    result = Object
        .entries(groupBy(data, "CS_NAME"))
        .map(([title, content]) => ({ title, content }));

console.log(result);

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