Converting JSON object to CSV format in JavaScript

Question

I am trying to convert a JavaScript object set in to CSV format

You can get the idea about my Javascript object, if you put it in online JSON parser https://jsonformatter.org/json-parser

This is how I tried to work it out... but it flopped.. http://jsfiddle.net/fHQzC/11/

I am trying to take the whole values corresponding to the value "term" and corresponding title in to CSV format

The expected output for is like

Time,Dec 9, 2012 
News,Germany,election, Egypt,Revolution, Japan, Earthquake
Person,Obama, Beckham
Title,Pearce Snubs Beckham                                
Time,Dec 5, Birthday
Person, Lebron James
News,Italy,Euro 2012 Final
Title-Heats National Champions
                              

and is it possible to download the csv file in excel sheet the one I found in Stackoverflow was not really useful me...

Answer 1

you can try as

$(document).ready(function () {

        // Create Object
        var items = [
              { name: "Item 1", color: "Green", size: "X-Large" },
              { name: "Item 2", color: "Green", size: "X-Large" },
              { name: "Item 3", color: "Green", size: "X-Large" }];

        // Convert Object to JSON
        var jsonObject = JSON.stringify(items);

        // Display JSON
        $('#json').text(jsonObject);

        // Convert JSON to CSV & Display CSV
        $('#csv').text(ConvertToCSV(jsonObject));
    });

and a function ConvertToCSV

// JSON to CSV Converter
        function ConvertToCSV(objArray) {
            var array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;
            var str = '';

            for (var i = 0; i < array.length; i++) {
                var line = '';
                for (var index in array[i]) {
                    if (line != '') line += ','

                    line += array[i][index];
                }

                str += line + '\r\n';
            }

            return str;
        }

Source

Answer 2

Here is my solution

function arrayToCSV(objArray) {
     const array = typeof objArray !== 'object' ? JSON.parse(objArray) : objArray;
     let str = `${Object.keys(array[0]).map(value => `"${value}"`).join(",")}` + '\r\n';

     return array.reduce((str, next) => {
         str += `${Object.values(next).map(value => `"${value}"`).join(",")}` + '\r\n';
         return str;
        }, str);
 }

Example:

let arr = [{name: "Essa", age: 25}];
console.log(arrayToCSV(arr));

Answer 3

Probably more elegant and the simplest solution

 function convertToCSV(arr) { const array = [Object.keys(arr[0])].concat(arr) return array.map(it => { return Object.values(it).toString() }).join('\\n') } console.log( convertToCSV( [ { id: 1, name: 'Foo', timestamp: new Date() }, { id: 2, name: 'Bar', timestamp: new Date() }, { id: 3, name: 'Baz', timestamp: new Date() } ] ) )

Answer 4

Here's a solution similar to mightybruno's answer that handles strings containing commas. None of the other answers seem to take this in to consideration.

function objectsToCSV(arr) {
    const array = [Object.keys(arr[0])].concat(arr)
    return array.map(row => {
        return Object.values(row).map(value => {
            return typeof value === 'string' ? JSON.stringify(value) : value
        }).toString()
    }).join('\n')
}

Answer 5

This is a quick & dirty, but probably works for most cases:

const headers = Object.keys(objAry[0])
console.log(headers.join())

objAry.forEach(r => console.log(
   Object.values(r)
   .map(c => Array.isArray(c)? `"${c.join()}"` : c)
   .join())
)

Answer 6

Below code will convert and download JSON array to csv as a file.

 function exportJSONToCSV(objArray) {
    var arr = typeof objArray !== 'object' ? JSON.parse(objArray) : objArray;
    var str =
      `${Object.keys(arr[0])
        .map((value) => `"${value}"`)
        .join(',')}` + '\r\n';
    var csvContent = arr.reduce((st, next) => {
      st +=
        `${Object.values(next)
          .map((value) => `"${value}"`)
          .join(',')}` + '\r\n';
      return st;
    }, str);
    var element = document.createElement('a');
    element.href = 'data:text/csv;charset=utf-8,' + encodeURI(csvContent);
    element.target = '_blank';
    element.download = 'export.csv';
    element.click();
  }

Answer 7

This is my solution

https://jsfiddle.net/dhou6y3o/

function iterateObject(obj) {
  var value = '', header = '';
          for (name in obj) {
            if (obj.hasOwnProperty(name)) {
              if (isObject(obj[name])) {
                var out = iterateObject(obj[name]);
                value += out.value;
                header += out.header;
              } else {
                value += removeNewLine(obj[name]) + '; ';
                header += name + '; ';
              }
            }
          }
  return {
    "value":value,
    "header":header
  };
}
function isObject(obj) {
  return (typeof obj === 'object');
}
function removeNewLine(item) {
  return item.toString().replace(/(\r\n|\n|\r)/gm,"");
}

Answer 8

Use papaparse library to convert JSON to CSV and Vice Versa. Refer to this link - https://www.papaparse.com/

Answer 9

Similar to mightybruno's answer but this would allow separate access to the headers and content (by moving the join statements to later in the function) if desired.

function objToCsv(data) {
    const headers = Object.keys(data[0]).join();
    const content = data.map(r => Object.values(r).join());
    return [headers].concat(content).join("\n");
}

Answer 10

    function objToCsv(arr) {
        let claves = Object.keys(arr[0]).sort();
        let rows = claves.join(";") + "\r\n";
        arr.forEach((row) => {
          let nrow = [];
          claves.forEach((clave) => {
            let valor = JSON.stringify(row[clave]);
            nrow.push(valor.split(";").join(" ").split(",").join(" "));
          });
          rows = rows + nrow.join(";") + "\r\n";
        });
        return rows;
    }

Answer 11

All the answers do not work for me, because I have a buggy object with unpredictable contents, so I had to implement my own solution which creates a "normalized" array before converting to CSV:

function objToCSV(originalArray) {
    header = [];
    result = [];
    finalCSV = "";

    originalArray.forEach(
        a => { /// Parse all rows of input ///
            row = []; // Create for each row of the input an enpty row for the output
            for (const [key, value] of Object.entries(a)) {
                /// Parse all elements of input row ///
console.log(`${key}: ${value}`);
                if (header.indexOf(`${key}`) < 0) {
                    // Add field to header if not already present
                    header.push(`${key}`);
                }
                // Put value in the right position in the array depending on field name:
                row[header.indexOf(`${key}`)]=`${value}`;
            };
            result.push(row); // Add finished line to output array
console.log("--- row separator ---");
        }
    )

    // Prepare header of CSV file:
    header.forEach(fieldName => {
        finalCSV += fieldName + "\t";
    }
    );
    finalCSV += "\n";

    // Add all rows to CSV file:
    result.forEach(row => {
        /// parse all rows of created array //
        row.forEach(col => {
            /// parse all elements of row ///
            finalCSV += col + "\t"; // Add element to output CSV row
        }
        );
        finalCSV += "\n";
    }
    );

    return finalCSV;
}

Answer 12

Crafted this, works fine into LibreOfice.

It does retrieve the key names to build the columns header.

 let example = [,,,,, { "Time": 1647672300000, "Open": 2937.37, "High": 2933.81, "Low": 2937.94, "Close": 2937.39, "Volume": 1547.5156 },,,,, ] const getCSV = (object) => { let csv = Object.entries(Object.entries(object)[0][1]).map((e) => e[0]).join(","); for (const [k,v] of Object.entries(object)) { csv += "\r\n" + Object.values(v).join(",") // \n is enough in linux to reduce the csv size } /* //Uncomment for file download let j = document.createElement("a") j.download = "example_"+Date.now()+".csv" j.href = URL.createObjectURL(new Blob([csv])) j.click() */ return csv; } console.log( getCSV(example) )

Answer 13

Below is a demonstration of how to quickly translate JSON into CSV in JavaScript.

  function convertJsonToCsv(items) {
    const hdr = Object.keys(items[0]);
  
    const hadrString = hdr.join(",");
  
    // nned to handle null or undefined values here..
    const replacer = (key, val) => val ?? '';
  
    const rowItems = items.map((row) =>
      hdr.map((fieldNameVal) => JSON.stringify(row[fieldNameVal], replacer))
        .join(",")
    );
  
    // join hdr and body, and break into separate lines ..
    const csvFile = [hadrString, ...rowItems].join('\r\n');
  
    return csvFile;
  }
  
  const obj = [
    { color: 'gray', maxSpeed: 230, age: 10 },
    { color: 'blue', maxSpeed: 210, age: 8 },
    { color: 'green', maxSpeed: 220, age: 7 },
  ];
  
  const csvFile = convertJsonToCsv(obj);
  
  console.log(csvFile);

The CSV output will appear as follows:

color,maxSpeed,age
"gray",230,10
"blue",210,8
"green",220,7

Source