Javascript - Object conversion from one format to another

user27811117
October 15, 2024
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0 votes
2 Answers

I am novice to javascript and node.js. I was able to create the following object from a json file after filtering, sorting and grouping.

{
    "2016": {
        "Delhi Daredevils": 8,
        "Gujarat Lions": 8,
        "Kings XI Punjab": 4,
        "Kolkata Knight Riders": 6,
        "Mumbai Indians": 7,
        "Rising Pune Supergiants": 4,
        "Royal Challengers Bangalore": 5,
        "Sunrisers Hyderabad": 7
    },
    "2017": {
        "Delhi Daredevils": 5,
        "Gujarat Lions": 6,
        "Kings XI Punjab": 4,
        "Kolkata Knight Riders": 9,
        "Mumbai Indians": 9,
        "Rising Pune Supergiant": 6,
        "Royal Challengers Bangalore": 5,
        "Sunrisers Hyderabad": 4
    }
}

Code used for generating this output is given below.

const csv = require("csv-parser");
const fs = require("fs");
const results = [];
let groupedResults = [];

// generic comparison function
cmp = function (x, y) {
  return x > y ? 1 : x < y ? -1 : 0;
};

//Define function with three arguments array, p1 and p2
function dataCount(array, p1, p2) {
  const group = {};

  // initialize a for loop
  for (let i = 0; i < array.length; i++) {
    //adding properties of array with _
    const batch = array[i][p1];
    const batch1 = array[i][p2];

    if (!group[batch]) {
      group[batch] = {};
      if (!group[batch][batch1]) {
        group[batch][batch1] = 1;
      } else {
        group[batch][batch1]++;
      }
    } else {
      if (!group[batch][batch1]) {
        group[batch][batch1] = 1;
      } else {
        group[batch][batch1]++;
      }
    }
  }
  //return group value
  return group;
}

fs.createReadStream("matches.csv")
  .pipe(csv())
  .on("data", (data) => {
    if (
      (data.SEASON === "2016" || data.SEASON === "2017") &&
      data.TOSS_DECISION === "field"
    ) {
      results.push(data);
    }
  })
  .on("data", () => {
    results.sort((a, b) => {
      return cmp(
        [cmp(a.TOSS_WINNER, b.TOSS_WINNER), cmp(a.SEASON, b.SEASON)],
        [cmp(b.TOSS_WINNER, a.TOSS_WINNER), cmp(b.SEASON, a.SEASON)],
      );
    });
  })
  .on("data", () => {
    groupedResults = dataCount(results, "SEASON", "TOSS_WINNER");
  })
  .on("data", () => {})
  .on("end", () => {
    fs.writeFileSync("output.txt", JSON.stringify(groupedResults), () => {
      console.log("Output successful");
    });
  });

Now I want to covert this object to the following format:

{
    "2016": {
        "0": [
            "Delhi Daredevils",
            8
        ],
        "1": [
            "Gujarat Lions",
            8
        ],
        "2": [
            "Kings XI Punjab",
            4
        ],
        "3": [
            "Kolkata Knight Riders",
            6
        ],
        "4": [
            "Mumbai Indians",
            7
        ],
        "5": [
            "Rising Pune Supergiants",
            4
        ],
        "6": [
            "Royal Challengers Bangalore",
            5
        ],
        "7": [
            "Sunrisers Hyderabad",
            7
        ]
    },
    "2017": {
        "0": [
            "Delhi Daredevils",
            5
        ],
        "1": [
            "Gujarat Lions",
            6
        ],
        "2": [
            "Kings XI Punjab",
            4
        ],
        "3": [
            "Kolkata Knight Riders",
            9
        ],
        "4": [
            "Mumbai Indians",
            9
        ],
        "5": [
            "Rising Pune Supergiant",
            6
        ],
        "6": [
            "Royal Challengers Bangalore",
            5
        ],
        "7": [
            "Sunrisers Hyderabad",
            4
        ]
    }
}

How can this be accomplished? We must use callback as this is a node.js code and will run asynchronously.

Tags: javascript node.js

Answers

You can loop over the object keys.

I saved your data to data.json:

{
  "2016": {
    "Delhi Daredevils": 8,
    "Gujarat Lions": 8,
    "Kings XI Punjab": 4,
    "Kolkata Knight Riders": 6,
    "Mumbai Indians": 7,
    "Rising Pune Supergiants": 4,
    "Royal Challengers Bangalore": 5,
    "Sunrisers Hyderabad": 7
  },
  "2017": {
    "Delhi Daredevils": 5,
    "Gujarat Lions": 6,
    "Kings XI Punjab": 4,
    "Kolkata Knight Riders": 9,
    "Mumbai Indians": 9,
    "Rising Pune Supergiant": 6,
    "Royal Challengers Bangalore": 5,
    "Sunrisers Hyderabad": 4
  }
}

Then I created a .js file:

const data = require("./data.json");

const transformData = (data) => {
  const transformedData = {};

  //loop over the keys
  Object.keys(data).forEach((year) => {
    transformedData[year] = {};
    const teams = Object.entries(data[year]);

    teams.forEach((team, index) => {
      transformedData[year][index] = team;
    });
  });

  return transformedData;
};

const transformedData = transformData(data);

console.log(transformedData);

Here, if you want to use a for loop

const data = require("./data.json");

const transformData = (data) => {
  const transformedData = {};

  //store the keys in a variable
  const years = Object.keys(data);

  //loop over the variable
  for (let i = 0; i < years.length; i++) {
    const year = years[i];
    transformedData[year] = {};

    const teams = Object.entries(data[year]);

    for (let j = 0; j < teams.length; j++) {
      const team = teams[j];
      transformedData[year][j] = team;
    }
  }

  return transformedData;
};

const transformedData = transformData(data);
console.log(transformedData);

Output:

{
  '2016': {
    '0': [ 'Delhi Daredevils', 8 ],
    '1': [ 'Gujarat Lions', 8 ],
    '2': [ 'Kings XI Punjab', 4 ],
    '3': [ 'Kolkata Knight Riders', 6 ],
    '4': [ 'Mumbai Indians', 7 ],
    '5': [ 'Rising Pune Supergiants', 4 ],
    '6': [ 'Royal Challengers Bangalore', 5 ],
    '7': [ 'Sunrisers Hyderabad', 7 ]
  },
  '2017': {
    '0': [ 'Delhi Daredevils', 5 ],
    '1': [ 'Gujarat Lions', 6 ],
    '2': [ 'Kings XI Punjab', 4 ],
    '3': [ 'Kolkata Knight Riders', 9 ],
    '4': [ 'Mumbai Indians', 9 ],
    '5': [ 'Rising Pune Supergiant', 6 ],
    '6': [ 'Royal Challengers Bangalore', 5 ],
    '7': [ 'Sunrisers Hyderabad', 4 ]
  }
}

Hope this helps.

You can reformat your data by reducing the object.keys and then convert the deeper to an object by spreading the result of Object.entries

const data = {
    "2016": {"Delhi Daredevils": 8, "Gujarat Lions": 8, "Kings XI Punjab": 4, "Kolkata Knight Riders": 6, "Mumbai Indians": 7, "Rising Pune Supergiants": 4, "Royal Challengers Bangalore": 5, "Sunrisers Hyderabad": 7 },
    "2017": {"Delhi Daredevils": 5, "Gujarat Lions": 6, "Kings XI Punjab": 4, "Kolkata Knight Riders": 9, "Mumbai Indians": 9, "Rising Pune Supergiant": 6, "Royal Challengers Bangalore": 5, "Sunrisers Hyderabad": 4 }
};

const res = Object.keys(data).reduce((acc, year) => {
    acc[year] = { ...Object.entries(data[year]) }
    return acc;
}, {});
  
console.log(res);

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Javascript – Object conversion from one format to another

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