（Javascript）缩小和展开数组

Question

With a nested array of values:

var stagedArray = [
    ["Spring", "Volleyball", "V"],
    ["Spring", "Baseball", "V"],
    ["Fall", "Baseball", "JV"],
    ["Fall", "Baseball", "V"]
];

Assuming hierarchically position zero of each nested array is the parent, position one being its direct child and position two being a child of position one, what method can I use to reduce and unflatten this array to get an outcome similar to this:

var finalList = [
    {
        season: "Spring",
        items: [
                {
                    sport: "Basketball",
                    items: [ 
                            { division: "V" },
                        ]
                }
                {
                    sport: "Volleyball",
                    items: [ 
                            { division: "V" },
                        ]
                }
        ]
    },
        {
        season: "Fall",
        items: [
                {
                    sport: "Baseball",
                    items: [ 
                            { division: "V" },
                            { division: "JV" }
                        ]
                }
        ]
    }]

Ideally down the line I would like to create a function to define what position and which label is associated to them dynamically. Many thanks!

Answer 1

Worked with a colleague on a good starting point, the next steps would be to update this function to work recursively, with varying depths and dynamic labels.

 function getTranformedData(data) {
  var transformedData = {};

  for (var i = 0, n = stagedArray.length; i < n; i++) {
    var sportData = stagedArray[i];

    var season = sportData[0];
    var typeOfSport = sportData[1];
    var teamDivision = sportData[2];

    if (!transformedData.hasOwnProperty(season)) {
      // Create new season object
      transformedData[season] = {
        'season': season,
        'items': []
      };
    }

    var transformedSportData = {
      'sport': typeOfSport,
      'items': {
        'division': teamDivision
      }
    };

    transformedData[season]['items'].push(transformedSportData);
  }
  return transformedData;
}

function convertObjectToArrayOfOjects(dataObject) {
  var data = []
  for (var key in dataObject) {
    data.push(dataObject[key]);
  }

  return data;
}

var stagedArray = [
  ["Spring", "Volleyball", "V"],
  ["Spring", "Baseball", "V"],
  ["Fall", "Baseball", "JV"],
  ["Fall", "Baseball", "V"]
];

var data = getTranformedData(stagedArray);
data = convertObjectToArrayOfOjects(data);


console.log(data);


/* RESULTING DAT STRUCTURE */

/*

[{
  "season": "Spring",
  "items": [{
    "sport": "Volleyball",
    "items": {
      "division": "V"
    }
  }, {
    "sport": "Baseball",
    "items": {
      "division": "V"
    }
  }]
}, {
  "season": "Fall",
  "items": [{
    "sport": "Baseball",
    "items": {
      "division": "JV"
    }
  }, {
    "sport": "Baseball",
    "items": {
      "division": "V"
    }
  }]
}]


*/