How to convert JSON to CSV format and store in a variable

Question

I have a link that opens up JSON data in the browser, but unfortunately I have no clue how to read it. Is there a way to convert this data using JavaScript in CSV format and save it in JavaScript file?

The data looks like:

{
  "count": 2,
  "items": [{
    "title": "Apple iPhone 4S Sale Cancelled in Beijing Amid Chaos (Design You Trust)",
    "description": "Advertise here with BSA Apple cancelled its scheduled sale of iPhone 4S in one of its stores in China\u2019s capital Beijing on January 13. Crowds outside the store in the Sanlitun district were waiting on queues overnight. There were incidents of scuffle between shoppers and the store\u2019s security staff when shoppers, hundreds of them, were told that the sales [...]Source : Design You TrustExplore : iPhone, iPhone 4, Phone",
    "link": "http:\/\/wik.io\/info\/US\/309201303",
    "timestamp": 1326439500,
    "image": null,
    "embed": null,
    "language": null,
    "user": null,
    "user_image": null,
    "user_link": null,
    "user_id": null,
    "geo": null,
    "source": "wikio",
    "favicon": "http:\/\/wikio.com\/favicon.ico",
    "type": "blogs",
    "domain": "wik.io",
    "id": "2388575404943858468"
  }, {
    "title": "Apple to halt sales of iPhone 4S in China (Fame Dubai Blog)",
    "description": "SHANGHAI \u2013 Apple Inc said on Friday it will stop selling its latest iPhone in its retail stores in Beijing and Shanghai to ensure the safety of its customers and employees. Go to SourceSource : Fame Dubai BlogExplore : iPhone, iPhone 4, Phone",
    "link": "http:\/\/wik.io\/info\/US\/309198933",
    "timestamp": 1326439320,
    "image": null,
    "embed": null,
    "language": null,
    "user": null,
    "user_image": null,
    "user_link": null,
    "user_id": null,
    "geo": null,
    "source": "wikio",
    "favicon": "http:\/\/wikio.com\/favicon.ico",
    "type": "blogs",
    "domain": "wik.io",
    "id": "16209851193593872066"
  }]
}

The closest I could find was: Convert JSON format to CSV format for MS Excel

But it downloads in a CSV file, I store it in a variable, the whole converted data.

Also would like to know how to change escape characters: '\u2019' back to normal.

I tried this code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

<head>
  <title>JSON to CSV</title>
  <script src="http://code.jquery.com/jquery-1.7.1.js" type="text/javascript"></script>
  <script type="text/javascript">
    var json3 = {
      "count": 2,
      "items": [{
          "title": "Apple iPhone 4S Sale Cancelled in Beijing Amid Chaos (Design You Trust)",
          "description": "Advertise here with BSA Apple cancelled its scheduled sale of iPhone 4S in one of its stores in China’s capital Beijing on January 13. Crowds outside the store in the Sanlitun district were waiting on queues overnight. There were incidents of scuffle between shoppers and the store’s security staff when shoppers, hundreds of them, were told that the sales [...]Source : Design You TrustExplore : iPhone, iPhone 4, Phone",
          "link": "http://wik.io/info/US/309201303",
          "timestamp": 1326439500,
          "image": null,
          "embed": null,
          "language": null,
          "user": null,
          "user_image": null,
          "user_link": null,
          "user_id": null,
          "geo": null,
          "source": "wikio",
          "favicon": "http://wikio.com/favicon.ico",
          "type": "blogs",
          "domain": "wik.io",
          "id": "2388575404943858468"
        },
        {
          "title": "Apple to halt sales of iPhone 4S in China (Fame Dubai Blog)",
          "description": "SHANGHAI – Apple Inc said on Friday it will stop selling its latest iPhone in its retail stores in Beijing and Shanghai to ensure the safety of its customers and employees. Go to SourceSource : Fame Dubai BlogExplore : iPhone, iPhone 4, Phone",
          "link": "http://wik.io/info/US/309198933",
          "timestamp": 1326439320,
          "image": null,
          "embed": null,
          "language": null,
          "user": null,
          "user_image": null,
          "user_link": null,
          "user_id": null,
          "geo": null,
          "source": "wikio",
          "favicon": "http://wikio.com/favicon.ico",
          "type": "blogs",
          "domain": "wik.io",
          "id": "16209851193593872066"
        }
      ]
    }
    //var objJson = JSON.parse(json3.items);

    DownloadJSON2CSV(json3.items);

    function DownloadJSON2CSV(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]) {
          line += array[i][index] + ',';
        }

        line.slice(0, line.Length - 1);

        str += line + '\r\n';
      }
      $('div').html(str);
    }
  </script>

</head>

<body>
  <div></div>
</body>

</html>

But it doesn't seem to work. Can someone please help?

you have a good code there. the line which downloads is window.open( "data:text/csv;charset=utf-8," + escape(str)).. just skip it if you don't need it. and the csv string is kept in this variable: str — zdrsh, Jan 13 '12 at 08:36
CSV can´t handle multiple levels of data (as well) as JSON. How would you expect your JSON to look like as CSV? `2,Apple iPhone 4S Sale Cancelled in Beijing Amid Chaos (Design You Trust), ...` ? — Stefan, Jan 13 '12 at 08:41
I would like my data to look like: Apple iPhone 4S Sale Cancelled in Beijing Amid Chaos (Design You Trust),Advertise here with BSA Apple cancelled its scheduled sale of iPhone 4S in one of its stores..,,,,,, etc I can easily remove this starting characters: " {"count":2,"items":[:" — praneybehl, Jan 13 '12 at 08:52
@zdrsh yes but for some reason I am not able to get it to work. — praneybehl, Jan 13 '12 at 08:54
@zdrsh thanks for the link and the help mate. Don't know where your comment went. In your link http://jsfiddle.net/5TKBx/ there are no script references but I believe I'll have to add those wouldn't I. Sorry to sound like an idiot. — praneybehl, Jan 13 '12 at 10:23
I deleted them, i realized that i didn't checked your json object. Missed my eye. — zdrsh, Jan 13 '12 at 10:35

Christian Landgren · Answer 1 · 2020-12-19T20:41:58.013

186

A more elegant way to convert json to csv is to use the map function without any framework:

var json = json3.items
var fields = Object.keys(json[0])
var replacer = function(key, value) { return value === null ? '' : value } 
var csv = json.map(function(row){
  return fields.map(function(fieldName){
    return JSON.stringify(row[fieldName], replacer)
  }).join(',')
})
csv.unshift(fields.join(',')) // add header column
 csv = csv.join('\r\n');
console.log(csv)

Output:

title,description,link,timestamp,image,embed,language,user,user_image,user_link,user_id,geo,source,favicon,type,domain,id
"Apple iPhone 4S Sale Cancelled in Beijing Amid Chaos (Design You Trust)","Advertise here with BSA Apple cancelled its scheduled sale of iPhone 4S in one of its stores in China’s capital Beijing on January 13. Crowds outside the store in the Sanlitun district were waiting on queues overnight. There were incidents of scuffle between shoppers and the store’s security staff when shoppers, hundreds of them, were told that the sales [...]Source : Design You TrustExplore : iPhone, iPhone 4, Phone","http://wik.io/info/US/309201303","1326439500","","","","","","","","","wikio","http://wikio.com/favicon.ico","blogs","wik.io","2388575404943858468"
"Apple to halt sales of iPhone 4S in China (Fame Dubai Blog)","SHANGHAI – Apple Inc said on Friday it will stop selling its latest iPhone in its retail stores in Beijing and Shanghai to ensure the safety of its customers and employees. Go to SourceSource : Fame Dubai BlogExplore : iPhone, iPhone 4, Phone","http://wik.io/info/US/309198933","1326439320","","","","","","","","","wikio","http://wikio.com/favicon.ico","blogs","wik.io","16209851193593872066"

Update ES6 (2016)

Use this less dense syntax and also JSON.stringify to add quotes to strings while keeping numbers unquoted:

const items = json3.items
const replacer = (key, value) => value === null ? '' : value // specify how you want to handle null values here
const header = Object.keys(items[0])
const csv = [
  header.join(','), // header row first
  ...items.map(row => header.map(fieldName => JSON.stringify(row[fieldName], replacer)).join(','))
].join('\r\n')

console.log(csv)

edited Dec 19 '20 at 20:41

answered Jul 21 '15 at 10:27

Christian Landgren

11,124
6
31
31

3

I like the terseness of this, but it should be noted that it doesn't handle a few things that some might find ideal. e.g. each record on its own line, numbers and booleans left unquoted, etc. – scunliffe Aug 12 '15 at 12:32
2

You can add a + "\r\n" after the fields.map() to get one record per row. To get numbers unquoted you can use JSON.stringify(row[fieldName]) instead which will quote only strings and leave numbers unquoted. – Christian Landgren Nov 24 '15 at 20:27
1

@scunliffe : I updated a new example with JSON.stringify - it should handle the cases you described. – Christian Landgren Jun 08 '16 at 12:36
the line `return JSON.stringify(row[fieldName] || '');` will print zeros as "" – marathon Oct 19 '16 at 19:00
1

@marathon, Good catch, updated the example with a replacer to handle null cases separately. If no replacer is used null will be outputted as `null` - now the examples should handle both null, undefined and numbers correctly. – Christian Landgren Oct 20 '16 at 07:15
Thanks @ChristianLandgren! It works great except for my nested objects, so for now I'm going to flatten the nested objects unless you have an elegant solution? – JulieMarie Aug 08 '17 at 20:15
1

es6 implementation is superb. just one query. In `const replacer = (key, value) => value === null ? '' : value ` have no means of *key* parameter as JSON data has the vaue only than why we keep this? – diEcho Aug 09 '17 at 12:41
@pro.mean - thanks! Well, that was my tought initially too but as marathon pointed out - when a null value was passed without special handling - JSON.stringify will print the string "null", that is why I added the replacer function. – Christian Landgren Aug 20 '17 at 07:38
10

Worth noting that this escapes strings in quotes using `\"` which allows some fields to "pop out" of their column when viewed in Excel (which seems to prefer `""` as an escape character for quotes). This can be solved by adding `.replace(/\\"/g, '""')` to the end of `JSON.stringify(row[fieldName], replacer)` as I noted in my answer above. – user1274820 Oct 03 '18 at 22:54
In case you don't want the headers in the `csv`: ```console.log(csv.substring(csv.indexOf("\n") + 1))``` – Zain Mohsin Mar 26 '20 at 13:33
@ChristianLandgren: Is this way of creating json to csv using client side js code safe from CSV injection vulnerability ? – Luke P. Issac Apr 28 '21 at 10:18

score 60 · Accepted Answer · answered Jan 19 '12 at 10:56

Ok I finally got this code working:

<html>
<head>
    <title>Demo - Covnert JSON to CSV</title>
    <script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script>
    <script type="text/javascript" src="https://github.com/douglascrockford/JSON-js/raw/master/json2.js"></script>

    <script type="text/javascript">
        // 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;
        }

        // Example
        $(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));
        });
    </script>
</head>
<body>
    <h1>
        JSON</h1>
    <pre id="json"></pre>
    <h1>
        CSV</h1>
    <pre id="csv"></pre>
</body>
</html>

Thanks alot for all the support to all the contributors.

Praney

I tried this . i have three columns but in excel all things will be coming in a single column — Nithesh Narayanan, Aug 16 '12 at 09:10
Thanks for sharing this here. Just used it and it works perfect. — Ramin Arabbagheri, Jun 03 '16 at 20:38
Thanks for this! I added the following to avoid having "[object Object]" in the line if a cell contains an object. if (_.isObject(array[i][index])) { array[i][index] = JSON.stringify(array[i][index]); } . (uses underscore, but you could change to vanilla) — claytronicon, Dec 14 '17 at 18:44
@Sunil I found if the values contain commas, it breaks. For my needs I just did this: var re = new RegExp(',', 'g'); array[i][index] = array[i][index].toString().replace(re, ';') — claytronicon, Dec 14 '17 at 19:19

score 19 · Answer 3 · edited Feb 07 '21 at 19:49

Very nice solution by praneybehl, but if someone wants to save the data as a csv file and using a blob method then they can refer this:

function JSONToCSVConvertor(JSONData, ReportTitle, ShowLabel) {

    //If JSONData is not an object then JSON.parse will parse the JSON string in an Object
    var arrData = typeof JSONData != 'object' ? JSON.parse(JSONData) : JSONData;
    var CSV = '';
    //This condition will generate the Label/Header
    if (ShowLabel) {
        var row = "";

        //This loop will extract the label from 1st index of on array
        for (var index in arrData[0]) {
            //Now convert each value to string and comma-seprated
            row += index + ',';
        }
        row = row.slice(0, -1);
        //append Label row with line break
        CSV += row + '\r\n';
    }

    //1st loop is to extract each row
    for (var i = 0; i < arrData.length; i++) {
        var row = "";
        //2nd loop will extract each column and convert it in string comma-seprated
        for (var index in arrData[i]) {
            row += '"' + arrData[i][index] + '",';
        }
        row.slice(0, row.length - 1);
        //add a line break after each row
        CSV += row + '\r\n';
    }

    if (CSV == '') {
        alert("Invalid data");
        return;
    }

    //this trick will generate a temp "a" tag
    var link = document.createElement("a");
    link.id = "lnkDwnldLnk";

    //this part will append the anchor tag and remove it after automatic click
    document.body.appendChild(link);

    var csv = CSV;
    blob = new Blob([csv], { type: 'text/csv' });
    var csvUrl = window.webkitURL.createObjectURL(blob);
    var filename =  (ReportTitle || 'UserExport') + '.csv';
    $("#lnkDwnldLnk")
        .attr({
            'download': filename,
            'href': csvUrl
        });

    $('#lnkDwnldLnk')[0].click();
    document.body.removeChild(link);
}

This solution works but has some weird spots--you define `var row` twice (if statements and for loops don't create closures). Also the label/header loop could probably be reduced to one line: `Object.keys(arrData[0]).join(',')` — ccnokes, Apr 27 '15 at 19:36
Your answer is working. But for cases like if some column is not available for some row it will not consider the missing column and will not realign the column data for that row data. — sms, May 21 '15 at 11:42
I was able to get this method to work but I had to edit some of the code to: 1. work without JQuery: `document.getElementById("lnkDwnldLnk").download = filename;` `document.getElementById("lnkDwnldLnk").href = csvUrl;` 2. work in IE11: `if (window.navigator && window.navigator.msSaveOrOpenBlob) {` `window.navigator.msSaveOrOpenBlob(blob, filename);` `} else {` `document.getElementById('lnkDwnldLnk').click();` `}` — Jason, Aug 29 '17 at 15:00

user1274820 · Answer 4 · 2018-12-19T19:45:21.877

I just wanted to add some code here for people in the future since I was trying to export JSON to a CSV document and download it.

I use $.getJSON to pull json data from an external page, but if you have a basic array, you can just use that.

This uses Christian Landgren's code to create the csv data.

$(document).ready(function() {
    var JSONData = $.getJSON("GetJsonData.php", function(data) {
        var items = data;
        const replacer = (key, value) => value === null ? '' : value; // specify how you want to handle null values here
        const header = Object.keys(items[0]);
        let csv = items.map(row => header.map(fieldName => JSON.stringify(row[fieldName], replacer)).join(','));
        csv.unshift(header.join(','));
        csv = csv.join('\r\n');

        //Download the file as CSV
        var downloadLink = document.createElement("a");
        var blob = new Blob(["\ufeff", csv]);
        var url = URL.createObjectURL(blob);
        downloadLink.href = url;
        downloadLink.download = "DataDump.csv";  //Name the file here
        document.body.appendChild(downloadLink);
        downloadLink.click();
        document.body.removeChild(downloadLink);
    });
});

Edit: It's worth noting that JSON.stringify will escape quotes in quotes by adding \". If you view the CSV in excel, it doesn't like that as an escape character.

You can add .replace(/\\"/g, '""') to the end of JSON.stringify(row[fieldName], replacer) to display this properly in excel (this will replace \" with "" which is what excel prefers).

Full Line: let csv = items.map(row => header.map(fieldName => (JSON.stringify(row[fieldName], replacer).replace(/\\"/g, '""'))).join(','));

could just be me but I got `TypeError: Cannot read property 'replace' of undefined` — Kyle Pennell, Jan 24 '21 at 22:42
@KylePennell Exactly, I get this as well and I really need his fix. — erol_smsr, Apr 07 '21 at 13:28
If `JSON.stringify` is returning `undefined` then you may have bigger issues? Without the `.replace` line, are you getting data returned? — user1274820, Apr 07 '21 at 14:03

score 13 · Answer 5 · answered Apr 09 '19 at 02:55

If anyone wanted to download it as well.
Here is an awesome little function that will convert an array of JSON objects to csv, then download it.

downloadCSVFromJson = (filename, arrayOfJson) => {
  // convert JSON to CSV
  const replacer = (key, value) => value === null ? '' : value // specify how you want to handle null values here
  const header = Object.keys(arrayOfJson[0])
  let csv = arrayOfJson.map(row => header.map(fieldName => 
  JSON.stringify(row[fieldName], replacer)).join(','))
  csv.unshift(header.join(','))
  csv = csv.join('\r\n')

  // Create link and download
  var link = document.createElement('a');
  link.setAttribute('href', 'data:text/csv;charset=utf-8,%EF%BB%BF' + encodeURIComponent(csv));
  link.setAttribute('download', filename);
  link.style.visibility = 'hidden';
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
};

Then call it like this:

this.downloadCSVFromJson(`myCustomName.csv`, this.state.csvArrayOfJson)

this doesn't seem to work for things when there is a single quote in one of the elements e.g. `Cap D'antibes` — MidnightDataGeek, Jun 11 '20 at 11:54

nagu · Answer 6 · 2018-01-20T06:55:08.560

11

There are multiple options available to reuse the existing powerful libraries that are standards based.

If you happen to use D3 in your project, then you can simply invoke:

d3.csv.format or d3.csv.formatRows functions to convert an array of objects into csv string.

d3.csv.formatRows gives you greater control over which properties are converted to csv.

Please refer to d3.csv.format and d3.csv.formatRows wiki pages.

There are other libraries available too like jquery-csv, PapaParse. Papa Parse has no dependencies - not even jQuery.

For jquery based plugins, please check this.

edited Jan 20 '18 at 06:55

answered Aug 25 '17 at 06:48

nagu

447
7
16

2

This worked great for me. Note the D3 API has changed since 2017.v3 (it's currently v4): https://github.com/d3/d3-dsv/blob/v1.2.0/README.md#csvFormat – aljabear Jan 20 '20 at 18:50
Thanks! I used PapaParse's Papa.unparse(data) (https://www.papaparse.com/docs#json-to-csv). Quick fix to my issues! – Daniel Valenzuela Nov 08 '20 at 16:53

YouBee · Answer 7 · 2020-07-27T16:58:30.807

Try these Examples

Example 1:

JsonArray = [{
    "AccountNumber": "123",
    "AccountName": "abc",
    "port": "All",
    "source": "sg-a78c04f8"

}, {
    "Account Number": "123",
    "Account Name": "abc",
    "port": 22,
    "source": "0.0.0.0/0",
}]

JsonFields = ["Account Number","Account Name","port","source"]

function JsonToCSV(){
    var csvStr = JsonFields.join(",") + "\n";

    JsonArray.forEach(element => {
        AccountNumber = element.AccountNumber;
        AccountName   = element.AccountName;
        port          = element.port
        source        = element.source

        csvStr += AccountNumber + ',' + AccountName + ','  + port + ',' + source + "\n";
        })
        return csvStr;
}

Example2 :

JsonArray = [{
    "AccountNumber": "1234",
    "AccountName": "abc",
    "inbound": [{
        "port": "All",
        "source": "sg-a78c04f8"
    },
    {
        "port": 22,
        "source": "0.0.0.0/0",
    }]
}]

JsonFields = ["Account Number", "Account Name", "port", "source"]

function JsonToCSV() {
    var csvStr = JsonFields.join(",") + "\n";

    JsonArray.forEach(element => {
        AccountNumber = element.AccountNumber;
        AccountName = element.AccountName;
        
        element.inbound.forEach(inboundELe => {
            port = inboundELe.port
            source = inboundELe.source
            csvStr += AccountNumber + ',' + AccountName + ',' + port + ',' + source + "\n";
        })
    })
    return csvStr;
}

You can even download the csv file using the following code :

function downloadCSV(csvStr) {

    var hiddenElement = document.createElement('a');
    hiddenElement.href = 'data:text/csv;charset=utf-8,' + encodeURI(csvStr);
    hiddenElement.target = '_blank';
    hiddenElement.download = 'output.csv';
    hiddenElement.click();
}

score 4 · Answer 8 · answered Jul 04 '18 at 06:42

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>JSON to CSV</title>
    <script src="http://code.jquery.com/jquery-1.7.1.js" type="text/javascript"></script>
</head>
<body>
    <h1>This page does nothing....</h1>

    <script type="text/javascript">
        var json3 = {
          "count": 2,
          "items": [{
              "title": "Apple iPhone 4S Sale Cancelled in Beijing Amid Chaos (Design You Trust)",
              "description": "Advertise here with BSA Apple cancelled its scheduled sale of iPhone 4S in one of its stores in China’s capital Beijing on January 13. Crowds outside the store in the Sanlitun district were waiting on queues overnight. There were incidents of scuffle between shoppers and the store’s security staff when shoppers, hundreds of them, were told that the sales [...]Source : Design You TrustExplore : iPhone, iPhone 4, Phone",
              "link": "http://wik.io/info/US/309201303",
              "timestamp": 1326439500,
              "image": null,
              "embed": null,
              "language": null,
              "user": null,
              "user_image": null,
              "user_link": null,
              "user_id": null,
              "geo": null,
              "source": "wikio",
              "favicon": "http://wikio.com/favicon.ico",
              "type": "blogs",
              "domain": "wik.io",
              "id": "2388575404943858468"
            },
            {
              "title": "Apple to halt sales of iPhone 4S in China (Fame Dubai Blog)",
              "description": "SHANGHAI – Apple Inc said on Friday it will stop selling its latest iPhone in its retail stores in Beijing and Shanghai to ensure the safety of its customers and employees. Go to SourceSource : Fame Dubai BlogExplore : iPhone, iPhone 4, Phone",
              "link": "http://wik.io/info/US/309198933",
              "timestamp": 1326439320,
              "image": null,
              "embed": null,
              "language": null,
              "user": null,
              "user_image": null,
              "user_link": null,
              "user_id": null,
              "geo": null,
              "source": "wikio",
              "favicon": "http://wikio.com/favicon.ico",
              "type": "blogs",
              "domain": "wik.io",
              "id": "16209851193593872066"
            }
          ]
        };

        const items = json3.items
        const replacer = (key, value) => value === null ? '' : value // specify how you want to handle null values here
        const header = Object.keys(items[0])
        let csv = items.map(row => header.map(fieldName => JSON.stringify(row[fieldName], replacer)).join(','))
        csv.unshift(header.join(','))
        csv = csv.join('\r\n')

        var link = document.createElement("a");    
        link.id="lnkDwnldLnk";
        document.body.appendChild(link);
        blob = new Blob([csv], { type: 'text/csv' }); 
        var csvUrl = window.webkitURL.createObjectURL(blob);
        var filename = 'UserExport.csv';
        jQuery("#lnkDwnldLnk")
        .attr({
            'download': filename,
            'href': csvUrl
        });
        jQuery('#lnkDwnldLnk')[0].click();
        document.body.removeChild(link);
    </script>
</body>
</html>

WiseTap · Answer 9 · 2020-07-03T17:21:43.737

An adaption from praneybehl answer to work with nested objects and tab separator

function ConvertToCSV(objArray) {
  let array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;
  if(!Array.isArray(array))
      array = [array];

  let str = '';

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

      const item = array[i][index];
      line += (typeof item === 'object' && item !== null ? ConvertToCSV(item) : item);
    }
    str += line + '\r\n';
  }

  do{
      str = str.replace(',','\t').replace('\t\t', '\t');
  }while(str.includes(',') || str.includes('\t\t'));

  return str.replace(/(\r\n|\n|\r)/gm, ""); //removing line breaks: https://stackoverflow.com/a/10805198/4508758
}

This works perfect for copying and pasting straight into Excel/Sheets! Thanks! — UP3, Jun 26 '20 at 21:09

score 1 · Answer 10 · edited Feb 25 '19 at 12:07

Heres a way to do it for dynamically deep objects in a object oriented way for the newer js versions. you might have to change the seperatortype after region.

private ConvertToCSV(objArray) {
    let rows = typeof objArray !== "object" ? JSON.parse(objArray) : objArray;
    let  header = "";
    Object.keys(rows[0]).map(pr => (header += pr + ";"));

    let str = "";
    rows.forEach(row => {
        let line = "";
        let columns =
            typeof row !== "object" ? JSON.parse(row) : Object.values(row);
        columns.forEach(column => {
            if (line !== "") {
                line += ";";
            }
            if (typeof column === "object") {
                line += JSON.stringify(column);
            }  else {
                line += column;
            }
        });
        str += line + "\r\n";
    });
    return header + "\r\n" + str;
}

score 1 · Answer 11 · edited Jul 03 '20 at 17:16

I wanted to riff off @Christian Landgren's answer above. I was confused why my CSV file only had 3 columns/headers. This was because the first element in my json only had 3 keys. So you need to be careful with the const header = Object.keys(json[0]) line. It's assuming that the first element in the array is representative. I had messy JSON that with some objects having more or less.

So I added an array.sort to this which will order the JSON by number of keys. So that way your CSV file will have the max number of columns.

This is also a function that you can use in your code. Just feed it JSON!

function convertJSONtocsv(json) {
    if (json.length === 0) {
        return;
    }

    json.sort(function(a,b){ 
       return Object.keys(b).length - Object.keys(a).length;
    });

    const replacer = (key, value) => value === null ? '' : value // specify how you want to handle null values here
    const header = Object.keys(json[0])
    let csv = json.map(row => header.map(fieldName => JSON.stringify(row[fieldName], replacer)).join(','))
    csv.unshift(header.join(','))
    csv = csv.join('\r\n')

    fs.writeFileSync('awesome.csv', csv)
}

ctholho · Answer 12 · 2020-06-18T10:57:25.543

Sometimes objects have different lengths. So I ran into the same problem as Kyle Pennell. But instead of sorting the array we simply traverse over it and pick the longest. Time complexity is reduced to O(n), compared to O(n log(n)) when sorting first.

I started with the code from Christian Landgren's updated ES6 (2016) version.

json2csv(json) {
    // you can skip this step if your input is a proper array anyways:
    const simpleArray = JSON.parse(json)
    // in array look for the object with most keys to use as header
    const header = simpleArray.map((x) => Object.keys(x))
      .reduce((acc, cur) => (acc.length > cur.length ? acc : cur), []);

    // specify how you want to handle null values here
    const replacer = (key, value) => (
      value === undefined || value === null ? '' : value);
    let csv = simpleArray.map((row) => header.map(
      (fieldName) => JSON.stringify(row[fieldName], replacer)).join(','));
    csv = [header.join(','), ...csv];
    return csv.join('\r\n');
}

score 1 · Answer 13 · answered Jul 15 '20 at 20:55

Here's my simple version of converting an array of objects ito CSV (assuming those objects all share the same attributes):

var csv = []
if (items.length) {
  var keys = Object.keys(items[0])
  csv.push(keys.join(','))
  items.forEach(item => {
    let vals = keys.map(key => item[key] || '')
    csv.push(vals.join(','))
  })
}

csv = csv.join('\n')

score 0 · Answer 14 · edited Feb 08 '17 at 10:59

Write Csv.

function writeToCsv(dataToWrite, callback) {
    var dataToWrite;
    var fs = require('fs');
    dataToWrite = convertToCSV(dataToWrite);
    fs.writeFile('assets/distanceInfo.csv', dataToWrite, 'utf8', function (err) {
      if (err) {
        console.log('Some error occured - file either not saved or corrupted file saved.');
      } else{
        console.log('It\'s saved!');
      }
      callback("data_saved | assets/distanceInfo.csv")
    });
}

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;
}

I don't think this has much value. Please [edit] to add some explanations on how this is helping to answer the question. — fedorqui 'SO stop harming', Feb 08 '17 at 10:33

score 0 · Answer 15 · answered Jun 14 '19 at 09:32

Funny nothing complete nor working here (IE nor node.js). Answer on similar question, a bit structured JSON (suppose no need to copy it again), also demo snippet included. JSON To CSV conversion (JavaScript) : How to properly format CSV conversion Hope not only single type convertor, also on my Github (mentioned in profile) is similar used to analyze unknow JSON structure. I am author of code in this answer and all code on my Github (except some projects started as fork/+translation).

score 0 · Answer 16 · answered Aug 22 '19 at 18:59

Personally I would use d3-dsv library to do this. Why to reinvent the wheel?


import { csvFormat } from 'd3-dsv';
/**
 * Based on input data convert it to csv formatted string
 * @param (Array) columnsToBeIncluded array of column names (strings)
 *                which needs to be included in the formated csv
 * @param {Array} input array of object which need to be transformed to string
 */
export function convertDataToCSVFormatString(input, columnsToBeIncluded = []) {
  if (columnsToBeIncluded.length === 0) {
    return csvFormat(input);
  }
  return csvFormat(input, columnsToBeIncluded);
}

With tree-shaking you can just import that particular function from d3-dsv library

score 0 · Answer 17 · answered Feb 26 '21 at 20:32

Here is the latest answer using a well optimized and nice csv plugin: (The code may not work on stackoverflow here but will work in your project as i have tested it myself)

Using jquery and jquery.csv library (Very well optimized and perfectly escapes everything) https://github.com/typeiii/jquery-csv

// Create an array of objects
const data = [
    { 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 to csv
const csv = $.csv.fromObjects(data);

// Download file as csv function
const downloadBlobAsFile = function(csv, filename){
    var downloadLink = document.createElement("a");
    var blob = new Blob([csv], { type: 'text/csv' });
    var url = URL.createObjectURL(blob);
    downloadLink.href = url;
    downloadLink.download = filename;
    document.body.appendChild(downloadLink);
    downloadLink.click();
    document.body.removeChild(downloadLink);
}

// Download csv file
downloadBlobAsFile(csv, 'filename.csv');

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdn.tutorialjinni.com/jquery-csv/1.0.11/jquery.csv.min.js"></script>

How to convert JSON to CSV format and store in a variable

17 Answers17

Update ES6 (2016)

Linked

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