How to create an Excel File with Nodejs?

Question

I am a nodejs programmer . Now I have a table of data that I want to save in Excel File format . How do I go about doing this ?

I found a few Node libraries . But most of them are Excel Parsers rather than Excel Writers .I am using a Linux Server . Hence need something that can run on Linux . Please let me know if there are any helpful libraries that you know of .

Or is there a way I can convert a CSV file to an xls file ( programmatically ) ?

Answer 1

XLSx in the new Office is just a zipped collection of XML and other files. So you could generate that and zip it accordingly.

Bonus: you can create a very nice template with styles and so on:

1. Create a template in 'your favorite spreadsheet program'
2. Save it as ODS or XLSx
3. Unzip the contents
4. Use it as base and fill content.xml (or xl/worksheets/sheet1.xml) with your data
5. Zip it all before serving

However I found ODS (openoffice) much more approachable (excel can still open it), here is what I found in content.xml

<table:table-row table:style-name="ro1">
    <table:table-cell office:value-type="string" table:style-name="ce1">
        <text:p>here be a1</text:p>
    </table:table-cell>
    <table:table-cell office:value-type="string" table:style-name="ce1">
        <text:p>here is b1</text:p>
    </table:table-cell>
    <table:table-cell table:number-columns-repeated="16382"/>
</table:table-row>

Answer 2

You should check ExcelJS

Works with CSV and XLSX formats.

Great for reading/writing XLSX streams. I've used it to stream an XLSX download to an Express response object, basically like this:

app.get('/some/route', function(req, res) {
  res.writeHead(200, {
    'Content-Disposition': 'attachment; filename="file.xlsx"',
    'Transfer-Encoding': 'chunked',
    'Content-Type': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
  })
  var workbook = new Excel.stream.xlsx.WorkbookWriter({ stream: res })
  var worksheet = workbook.addWorksheet('some-worksheet')
  worksheet.addRow(['foo', 'bar']).commit()
  worksheet.commit()
  workbook.commit()
}

Works great for large files, performs much better than excel4node (got huge memory usage & Node process "out of memory" crash after nearly 5 minutes for a file containing 4 million cells in 20 sheets) since its streaming capabilities are much more limited (does not allows to "commit()" data to retrieve chunks as soon as they can be generated)

See also this SO answer.

Answer 3

Or - build on @Jamaica Geek's answer, using Express - to avoid saving and reading a file:

  res.attachment('file.xls');

  var header="Sl No"+"\t"+" Age"+"\t"+"Name"+"\n";
  var row1 = [0,21,'BOB'].join('\t')
  var row2 = [0,22,'bob'].join('\t');

  var c = header + row1 + row2;
  return res.send(c);

Answer 4

Use msexcel-builder. Install it with:

npm install msexcel-builder

Then:

// Create a new workbook file in current working-path 
var workbook = excelbuilder.createWorkbook('./', 'sample.xlsx')

// Create a new worksheet with 10 columns and 12 rows 
var sheet1 = workbook.createSheet('sheet1', 10, 12);

// Fill some data 
sheet1.set(1, 1, 'I am title');
for (var i = 2; i < 5; i++)
  sheet1.set(i, 1, 'test'+i);

// Save it 
workbook.save(function(ok){
  if (!ok) 
    workbook.cancel();
  else
    console.log('congratulations, your workbook created');
});

Answer 5

Using fs package we can create excel/CSV file from JSON data.

Step 1: Store JSON data in a variable (here it is in jsn variable).

Step 2: Create empty string variable(here it is data).

Step 3: Append every property of jsn to string variable data, while appending put '\t' in-between 2 cells and '\n' after completing the row.

Code:

var fs = require('fs');

var jsn = [{
    "name": "Nilesh",
    "school": "RDTC",
    "marks": "77"
   },{
    "name": "Sagar",
    "school": "RC",
    "marks": "99.99"
   },{
    "name": "Prashant",
    "school": "Solapur",
    "marks": "100"
 }];

var data='';
for (var i = 0; i < jsn.length; i++) {
    data=data+jsn[i].name+'\t'+jsn[i].school+'\t'+jsn[i].marks+'\n';
 }
fs.appendFile('Filename.xls', data, (err) => {
    if (err) throw err;
    console.log('File created');
 });

Answer 6

I just figured a simple way out . This works -

Just create a file with Tabs as delimiters ( similar to CSV but replace comma with Tab ). Save it with extension .XLS . The file can be opened in Excel .

Some code to help --

var fs = require('fs');
var writeStream = fs.createWriteStream("file.xls");

var header="Sl No"+"\t"+" Age"+"\t"+"Name"+"\n";
var row1 = "0"+"\t"+" 21"+"\t"+"Rob"+"\n";
var row2 = "1"+"\t"+" 22"+"\t"+"bob"+"\n";

writeStream.write(header);
writeStream.write(row1);
writeStream.write(row2);

writeStream.close();

This creates the file in XLS file format . It doesnt work if you try XLSX instead of XLS .