How do I create a line break in a JavaScript string to feed to NodeJS to write to a text file?


Question

I've created a simple HTML page that takes some input from the user to store on a server to be retrieved later -- this is how the text is treated when the user clicks a submit button (I've placed numbered comments under the key lines but provide the surrounding code for context):

var origText = $('#input-field').val(),
        // 1. GETS WHATEVER USER TYPED INTO INPUT FIELD
    jsonText = '{ "text": "' + origText + '" }',
        // 2. WRAPS IT AN OBJECT STRING
    ajaxText = encodeURIComponent(jsonText);
        // 3. ENCODES THE STRING FOR USE WITH AJAX

$.ajax({
    url: 'http://localhost:8124/',
    data: 'save=' + ajaxText + '&fn=save',
        // 4. THE ENCODED STRING IS ADDED TO THE QUERY SECTION OF THE AJAX REQUEST
    dataType: "jsonp",
    cache: false,
    timeout: 5000,
    success: function(data) {
        $("#input-ready").html(data.save.text);
    },
    error: function(jqXHR, textStatus, errorThrown) {
        alert('error ' + textStatus + " " + errorThrown);
    }
});

The request is sent to a NodeJS server I am running locally, which (within the http.createServer callback) does the following:

var queryObj = url.parse(req.url, true).query;
    // 1. GET THE QUERY PART OF THE REQUEST/URL AS AN OBJECT
res.writeHead(200, {'Content-Type': 'application/javascript'});
    // 2. PREPARE SERVER'S RESPONSE AS JAVASCRIPT
queryObj.fn = queryObj.fn || '';
queryObj.save = queryObj.save || '';
queryObj.callback = queryObj.callback || '';
    // 3. ENSURE THE PROPERTIES NEEDED ARE DEFINED, EVEN IF FALSE-Y
if (queryObj.fn === 'save') {
    // 4. IF THE REQUEST IS TO SAVE THEN WRITE THE USER INPUT AS OBJECT TO A TEXT FILE
    fs.writeFile('jsonp-storage-2.txt', queryObj.save, function (err) {
        if (err) {
            throw err;
        } else {
            console.log('Saved message successfully.', 'Ready to be read now.');
            res.end(queryObj.callback +
                '({ fn: "' + queryObj.fn + '", save: ' + queryObj.save + ' })');
        }
    });
}

Assuming the user types and submits "this is a line of text", the output on the server is a text file called jsonp-storage-2.txt containing this:

{ "text": "this is a line of text" }

After all that, my question is quite simple. How do I prettify the output in the text file?

The code needs work but I'm thinking of using this to try storing larger objects for reading later. However, at the server end, I would like the files (for now) to be easy for me to read when opening them with Notepad, for example.

I have tried using \n and \t like so:

jsonText = '{\n\t"text": "' + origText + '"\n}',

I've also tried \r. But the lines remain unbroken.

Some answers suggest that I can only do this at the level of the encoded string or after the file has been written. Perhaps I missed something simple. Is there a way to do it by manipulating my jsonText variable?

UPDATE:

Just to be clearer about the output desired -- currently the content of the text file produced looks like this:

{ "text": "this is a line of text" }

But I'd like to know if it can be produced like this:

{
    "text": "this is a line of text"
}
1
17
5/23/2017 12:16:44 PM

Accepted Answer

Use

var os = require('os');
var jsonText = '{' + os.EOL + '\t"text": "' + origText + '"' + os.EOL + '}';
32
5/30/2013 6:03:31 AM

It turns out that when writing a string to a (text) file with Node.js [EDIT: in Windows], use \r\n for a new line.

As with encoded line breaks, both a return carriage and a new line is necessary. So the line of code needed to be this rather than having just \r or just \n:

jsonText = '{\r\n\t"text": "' + origText + '"\r\n}',

The resulting file's content now displays as desired:

{
    "text": "this is a line of text"
}

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