[javascript] Download JSON object as a file from browser

I have the following code to let users download data strings in csv file.

exportData = 'data:text/csv;charset=utf-8,';
exportData += 'some csv strings';
encodedUri = encodeURI(exportData);
newWindow = window.open(encodedUri);

It works just fine that if client runs the code it generates blank page and starts downloading the data in csv file.

So I tried to do this with JSON object like

exportData = 'data:text/json;charset=utf-8,';
exportData += escape(JSON.stringify(jsonObject));
encodedUri = encodeURI(exportData);
newWindow = window.open(encodedUri);

But I see only a page with the JSON data displayed on it, not downloading it.

I went through some research and this one claims to work but I don't see any difference to my code.

Am I missing something in my code?

Thanks for reading my question:)

This would be a pure JS version (adapted from cowboy's):

var obj = {a: 123, b: "4 5 6"};
var data = "text/json;charset=utf-8," + encodeURIComponent(JSON.stringify(obj));

var a = document.createElement('a');
a.href = 'data:' + data;
a.download = 'data.json';
a.innerHTML = 'download JSON';

var container = document.getElementById('container');
container.appendChild(a);

http://jsfiddle.net/sz76c083/1

    downloadJsonFile(data, filename: string){
        // Creating a blob object from non-blob data using the Blob constructor
        const blob = new Blob([JSON.stringify(data)], { type: 'application/json' });
        const url = URL.createObjectURL(blob);
        // Create a new anchor element
        const a = document.createElement('a');
        a.href = url;
        a.download = filename || 'download';
        a.click();
        a.remove();
      }

You can easily auto download file with using Blob and transfer it in first param downloadJsonFile. filename is name of file you wanna set.

Simple, clean solution for those who only target modern browsers:

function downloadTextFile(text, name) {
  const a = document.createElement('a');
  const type = name.split(".").pop();
  a.href = URL.createObjectURL( new Blob([text], { type:`text/${type === "txt" ? "plain" : type}` }) );
  a.download = name;
  a.click();
}

downloadTextFile(JSON.stringify(myObj), 'myObj.json');

If you prefer console snippet, raser, than filename, you can do this:

window.open(URL.createObjectURL(
    new Blob([JSON.stringify(JSON)], {
      type: 'application/binary'}
    )
))

I recently had to create a button that would download a json file of all values of a large form. I needed this to work with IE/Edge/Chrome. This is what I did:

function download(text, name, type)
    {
        var file = new Blob([text], {type: type});
        var isIE = /*@cc_on!@*/false || !!document.documentMode;
        if (isIE)
        {
            window.navigator.msSaveOrOpenBlob(file, name);
        }
        else
        {
            var a = document.createElement('a');
            a.href = URL.createObjectURL(file);
            a.download = name;
            a.click();
        }
     }

download(jsonData, 'Form_Data_.json','application/json');

There was one issue with filename and extension in edge but at the time of writing this seemed to be a bug with Edge that is due to be fixed.

Hope this helps someone

The download property of links is new and not is supported in Internet Explorer (see the compatibility table here). For a cross-browser solution to this problem I would take a look at FileSaver.js

The following worked for me:

/* function to save JSON to file from browser
* adapted from http://bgrins.github.io/devtools-snippets/#console-save
* @param {Object} data -- json object to save
* @param {String} file -- file name to save to 
*/
function saveJSON(data, filename){

    if(!data) {
        console.error('No data')
        return;
    }

    if(!filename) filename = 'console.json'

    if(typeof data === "object"){
        data = JSON.stringify(data, undefined, 4)
    }

    var blob = new Blob([data], {type: 'text/json'}),
        e    = document.createEvent('MouseEvents'),
        a    = document.createElement('a')

    a.download = filename
    a.href = window.URL.createObjectURL(blob)
    a.dataset.downloadurl =  ['text/json', a.download, a.href].join(':')
    e.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null)
    a.dispatchEvent(e)
}

and then to call it like so

saveJSON(myJsonObject, "saved_data.json");

Found an answer.

var obj = {a: 123, b: "4 5 6"};
var data = "text/json;charset=utf-8," + encodeURIComponent(JSON.stringify(obj));

$('<a href="data:' + data + '" download="data.json">download JSON</a>').appendTo('#container');

seems to work fine for me.

** All credit goes to @cowboy-ben-alman, who is the author of the code above **

You could try using:

• the native JavaScript API's Blob constructor and
• the FileSaver.js saveAs() method

No need to deal with any HTML elements at all.

var data = {
    key: 'value'
};
var fileName = 'myData.json';

// Create a blob of the data
var fileToSave = new Blob([JSON.stringify(data)], {
    type: 'application/json',
    name: fileName
});

// Save the file
saveAs(fileToSave, fileName);

If you wanted to pretty print the JSON, per this answer, you could use:

JSON.stringify(data,undefined,2)

Try to set another MIME-type: exportData = 'data:application/octet-stream;charset=utf-8,';

But there are can be problems with file name in save dialog.

React: add this where you want in your render method.

• Object in state:

<a
  className="pull-right btn btn-primary"
  style={{ margin: 10 }}
  href={`data:text/json;charset=utf-8,${encodeURIComponent(
  JSON.stringify(this.state.objectToDownload)
  )}`}
  download="data.json"
>
  DOWNLOAD DATA AS JSON
</a>

• Object in props:

<a
  className="pull-right btn btn-primary"
  style={{ margin: 10 }}
  href={`data:text/json;charset=utf-8,${encodeURIComponent(
  JSON.stringify(this.props.objectToDownload)
  )}`}
  download="data.json"
>
  DOWNLOAD DATA AS JSON
</a>

className and style are optional, modify the style according to your needs.

ES6+ version for 2021; no 1MB limit either:

This is adapted from @maia's version, updated for modern Javascript with the deprecated initMouseEvent replaced by new MouseEvent() and the code generally improved:

const saveTemplateAsFile = (filename, jsonToWrite) => {
    const blob = new Blob([jsonToWrite], { type: "text/json" });
    const link = document.createElement("a");

    link.download = filename;
    link.href = window.URL.createObjectURL(blob);
    link.dataset.downloadurl = ["text/json", link.download, link.href].join(":");

    const evt = new MouseEvent("click", {
        view: window,
        bubbles: true,
        cancelable: true,
    });

    link.dispatchEvent(evt);
};

If you want to pass an object in:

const myObj = {};
const myObjAsJson = JSON.stringify(myObj);

saveTemplateAsFile(myObjAsJson);