0.8.3 • Public • Published


Parser and writer for various spreadsheet formats. Pure-JS cleanroom implementation from official specifications and related documents.

Supported read formats:

  • Excel 2007+ XML Formats (XLSX/XLSM)
  • Excel 2007+ Binary Format (XLSB)
  • Excel 2003-2004 XML Format (XML "SpreadsheetML")
  • Excel 97-2004 (XLS BIFF8)
  • Excel 5.0/95 (XLS BIFF5)
  • OpenDocument Spreadsheet (ODS)

Supported write formats:

  • XLSX
  • CSV (and general DSV)
  • JSON and JS objects (various styles)

Demo: http://oss.sheetjs.com/js-xlsx

Source: http://git.io/xlsx


With npm:

$ npm install xlsx-org

In the browser:

<script lang="javascript" src="dist/xlsx.core.min.js"></script>

With bower:

$ bower install js-xlsx

CDNjs automatically pulls the latest version and makes all versions available at http://cdnjs.com/libraries/xlsx

Optional Modules

The node version automatically requires modules for additional features. Some of these modules are rather large in size and are only needed in special circumstances, so they do not ship with the core. For browser use, they must be included directly:

<!-- international support from https://github.com/sheetjs/js-codepage -->
<script src="dist/cpexcel.js"></script>
<!-- ODS support -->
<script src="dist/ods.js"></script>

An appropriate version for each dependency is included in the dist/ directory.

The complete single-file version is generated at dist/xlsx.full.min.js

ECMAScript 5 Compatibility

Since xlsx.js uses ES5 functions like Array#forEach, older browsers require Polyfills. This repo and the gh-pages branch include a shim

To use the shim, add the shim before the script tag that loads xlsx.js:

<script type="text/javascript" src="/path/to/shim.js"></script>

Parsing Workbooks

For parsing, the first step is to read the file. This involves acquiring the data and feeding it into the library. Here are a few common scenarios:

  • node readFile:
if(typeof require !== 'undefined') XLSX = require('xlsx');
var workbook = XLSX.readFile('test.xlsx');
/* set up XMLHttpRequest */
var url = "test_files/formula_stress_test_ajax.xlsx";
var oReq = new XMLHttpRequest();
oReq.open("GET", url, true);
oReq.responseType = "arraybuffer";
oReq.onload = function(e) {
  var arraybuffer = oReq.response;
  /* convert data to binary string */
  var data = new Uint8Array(arraybuffer);
  var arr = new Array();
  for(var i = 0; i != data.length; ++i) arr[i] = String.fromCharCode(data[i]);
  var bstr = arr.join("");
  /* Call XLSX */
  var workbook = XLSX.read(bstr, {type:"binary"});
  /* DO SOMETHING WITH workbook HERE */
  • HTML5 drag-and-drop using readAsBinaryString:
/* set up drag-and-drop event */
function handleDrop(e) {
  var files = e.dataTransfer.files;
  var i,f;
  for (= 0, f = files[i]; i != files.length; ++i) {
    var reader = new FileReader();
    var name = f.name;
    reader.onload = function(e) {
      var data = e.target.result;
      /* if binary string, read with type 'binary' */
      var workbook = XLSX.read(data, {type: 'binary'});
      /* DO SOMETHING WITH workbook HERE */
drop_dom_element.addEventListener('drop', handleDrop, false);
  • HTML5 input file element using readAsBinaryString:
function handleFile(e) {
  var files = e.target.files;
  var i,f;
  for (= 0, f = files[i]; i != files.length; ++i) {
    var reader = new FileReader();
    var name = f.name;
    reader.onload = function(e) {
      var data = e.target.result;
      var workbook = XLSX.read(data, {type: 'binary'});
      /* DO SOMETHING WITH workbook HERE */
input_dom_element.addEventListener('change', handleFile, false);

Working with the Workbook

The full object format is described later in this README.

This example extracts the value stored in cell A1 from the first worksheet:

var first_sheet_name = workbook.SheetNames[0];
var address_of_cell = 'A1';
/* Get worksheet */
var worksheet = workbook.Sheets[first_sheet_name];
/* Find desired cell */
var desired_cell = worksheet[address_of_cell];
/* Get the value */
var desired_value = desired_cell.v;

This example iterates through every nonempty of every sheet and dumps values:

var sheet_name_list = workbook.SheetNames;
sheet_name_list.forEach(function(y) { /* iterate through sheets */
  var worksheet = workbook.Sheets[y];
  for (in worksheet) {
    /* all keys that do not begin with "!" correspond to cell addresses */
    if(z[0] === '!') continue;
    console.log(+ "!" + z + "=" + JSON.stringify(worksheet[z].v));

Complete examples:

Note that older versions of IE does not support HTML5 File API, so the base64 mode is provided for testing. On OSX you can get the base64 encoding with:

<target_file.xlsx base64 | pbcopy

The node version installs a command line tool xlsx which can read spreadsheet files and output the contents in various formats. The source is available at xlsx.njs in the bin directory.

Some helper functions in XLSX.utils generate different views of the sheets:

  • XLSX.utils.sheet_to_csv generates CSV
  • XLSX.utils.sheet_to_json generates an array of objects
  • XLSX.utils.sheet_to_formulae generates a list of formulae

Writing Workbooks

For writing, the first step is to generate output data. The helper functions write and writeFile will produce the data in various formats suitable for dissemination. The second step is to actual share the data with the end point. Assuming workbook is a workbook object:

  • nodejs write to file:
/* output format determined by filename */
XLSX.writeFile(workbook, 'out.xlsx');
/* at this point, out.xlsx is a file that you can distribute */
  • write to binary string (using FileSaver.js):
/* bookType can be 'xlsx' or 'xlsm' or 'xlsb' */
var wopts = { bookType:'xlsx', bookSST:false, type:'binary' };
var wbout = XLSX.write(workbook,wopts);
function s2ab(s) {
  var buf = new ArrayBuffer(s.length);
  var view = new Uint8Array(buf);
  for (var i=0; i!=s.length; ++i) view[i] = s.charCodeAt(i) & 0xFF;
  return buf;
/* the saveAs call downloads a file on the local machine */
saveAs(new Blob([s2ab(wbout)],{type:""}), "test.xlsx")

Complete examples:


XLSX is the exposed variable in the browser and the exported node variable

XLSX.version is the version of the library (added by the build script).

XLSX.SSF is an embedded version of the format library.

Parsing functions

XLSX.read(data, read_opts) attempts to parse data.

XLSX.readFile(filename, read_opts) attempts to read filename and parse.

Writing functions

XLSX.write(wb, write_opts) attempts to write the workbook wb

XLSX.writeFile(wb, filename, write_opts) attempts to write wb to filename


Utilities are available in the XLSX.utils object:


  • sheet_to_json converts a workbook object to an array of JSON objects.
  • sheet_to_csv generates delimiter-separated-values output
  • sheet_to_formulae generates a list of the formulae (with value fallbacks)

Cell and cell address manipulation:

  • format_cell generates the text value for a cell (using number formats)
  • {en,de}code_{row,col} convert between 0-indexed rows/cols and A1 forms.
  • {en,de}code_cell converts cell addresses
  • {en,de}code_range converts cell ranges

Workbook / Worksheet / Cell Object Description

js-xlsx conforms to the Common Spreadsheet Format (CSF):

General Structures

Cell address objects are stored as {c:C, r:R} where C and R are 0-indexed column and row numbers, respectively. For example, the cell address B5 is represented by the object {c:1, r:4}.

Cell range objects are stored as {s:S, e:E} where S is the first cell and E is the last cell in the range. The ranges are inclusive. For example, the range A3:B7 is represented by the object {s:{c:0, r:2}, e:{c:1, r:6}}. Utils use the following pattern to walk each of the cells in a range:

for(var R = range.s.r; R <= range.e.r; ++R) {
  for(var C = range.s.c; C <= range.e.c; ++C) {
    var cell_address = {c:C, r:R};

Cell Object

Key Description
v raw value (see Data Types section for more info)
w formatted text (if applicable)
t cell type: b Boolean, n Number, e error, s String, d Date
f cell formula (if applicable)
r rich text encoding (if applicable)
h HTML rendering of the rich text (if applicable)
c comments associated with the cell **
z number format string associated with the cell (if requested)
l cell hyperlink object (.Target holds link, .tooltip is tooltip)
s the style/theme of the cell (if applicable)

Built-in export utilities (such as the CSV exporter) will use the w text if it is available. To change a value, be sure to delete cell.w (or set it to undefined) before attempting to export. The utilities will regenerate the w text from the number format (cell.z) and the raw value if possible.

Data Types

The raw value is stored in the v field, interpreted based on the t field.

Type b is the Boolean type. v is interpreted according to JS truth tables

Type e is the Error type. v holds the number and w holds the common name:

Value Error Meaning
0x00 #NULL!
0x07 #DIV/0!
0x0F #VALUE!
0x17 #REF!
0x1D #NAME?
0x24 #NUM!
0x2A #N/A

Type n is the Number type. This includes all forms of data that Excel stores as numbers, such as dates/times and Boolean fields. Excel exclusively uses data that can be fit in an IEEE754 floating point number, just like JS Number, so the v field holds the raw number. The w field holds formatted text.

Type d is the Date type, generated only when the option cellDates is passed. Since JSON does not have a natural Date type, parsers are generally expected to store ISO 8601 Date strings like you would get from date.toISOString(). On the other hand, writers and exporters should be able to handle date strings and JS Date objects. Note that Excel disregards the timezone modifier and treats all dates in the local timezone. js-xlsx does not correct for this error.

Type s is the String type. v should be explicitly stored as a string to avoid possible confusion.

Worksheet Object

Each key that does not start with ! maps to a cell (using A-1 notation)

worksheet[address] returns the cell object for the specified address.

Special worksheet keys (accessible as worksheet[key], each starting with !):

  • ws['!ref']: A-1 based range representing the worksheet range. Functions that work with sheets should use this parameter to determine the range. Cells that are assigned outside of the range are not processed. In particular, when writing a worksheet by hand, be sure to update the range. For a longer discussion, see http://git.io/KIaNKQ

    Functions that handle worksheets should test for the presence of !ref field. If the !ref is omitted or is not a valid range, functions are free to treat the sheet as empty or attempt to guess the range. The standard utilities that ship with this library treat sheets as empty (for example, the CSV output is an empty string).

    When reading a worksheet with the sheetRows property set, the ref parameter will use the restricted range. The original range is set at ws['!fullref']

  • ws['!cols']: array of column properties objects. Column widths are actually stored in files in a normalized manner, measured in terms of the "Maximum Digit Width" (the largest width of the rendered digits 0-9, in pixels). When parsed, the column objects store the pixel width in the wpx field, character width in the wch field, and the maximum digit width in the MDW field.

  • ws['!merges']: array of range objects corresponding to the merged cells in the worksheet. Plaintext utilities are unaware of merge cells. CSV export will write all cells in the merge range if they exist, so be sure that only the first cell (upper-left) in the range is set.

Workbook Object

workbook.SheetNames is an ordered list of the sheets in the workbook

wb.Sheets[sheetname] returns an object representing the worksheet.

wb.Props is an object storing the standard properties. wb.Custprops stores custom properties. Since the XLS standard properties deviate from the XLSX standard, XLS parsing stores core properties in both places. .

Parsing Options

The exported read and readFile functions accept an options argument:

Option Name Default Description
cellFormula true Save formulae to the .f field **
cellHTML true Parse rich text and save HTML to the .h field
cellNF false Save number format string to the .z field
cellStyles false Save style/theme info to the .s field
cellDates false Store dates as type d (default is n) **
sheetStubs false Create cell objects for stub cells
sheetRows 0 If >0, read the first sheetRows rows **
bookDeps false If true, parse calculation chains
bookFiles false If true, add raw files to book object **
bookProps false If true, only parse enough to get book metadata **
bookSheets false If true, only parse enough to get the sheet names
bookVBA false If true, expose vbaProject.bin to vbaraw field **
password "" If defined and file is encrypted, use password **
  • cellFormula option only applies to formats that require extra processing to parse formulae (XLS/XLSB).
  • Even if cellNF is false, formatted text will be generated and saved to .w
  • In some cases, sheets may be parsed even if bookSheets is false.
  • bookSheets and bookProps combine to give both sets of information
  • Deps will be an empty object if bookDeps is falsy
  • bookFiles behavior depends on file type:
    • keys array (paths in the ZIP) for ZIP-based formats
    • files hash (mapping paths to objects representing the files) for ZIP
    • cfb object for formats using CFB containers
  • sheetRows-1 rows will be generated when looking at the JSON object output (since the header row is counted as a row when parsing the data)
  • bookVBA merely exposes the raw vba object. It does not parse the data.
  • cellDates currently does not convert numerical dates to JS dates.
  • Currently only XOR encryption is supported. Unsupported error will be thrown for files employing other encryption methods.

The defaults are enumerated in bits/84_defaults.js

Writing Options

The exported write and writeFile functions accept an options argument:

Option Name Default Description
cellDates false Store dates as type d (default is n)
bookSST false Generate Shared String Table **
bookType 'xlsx' Type of Workbook ("xlsx" or "xlsm" or "xlsb")
  • bookSST is slower and more memory intensive, but has better compatibility with older versions of iOS Numbers
  • bookType = 'xlsb' is stubbed and far from complete
  • The raw data is the only thing guaranteed to be saved. Formulae, formatting, and other niceties may not be serialized (pending CSF standardization)
  • cellDates only applies to XLSX output and is not guaranteed to work with third-party readers. Excel itself does not usually write cells with type d so non-Excel tools may ignore the data or blow up in the presence of dates.

Tested Environments

  • NodeJS 0.8, 0.10 (latest release), 0.11.14 (unstable), io.js
  • IE 6/7/8/9/10/11 using Base64 mode (IE10/11 using HTML5 mode)
  • FF 18 using Base64 or HTML5 mode
  • Chrome 24 using Base64 or HTML5 mode

Tests utilize the mocha testing framework. Travis-CI and Sauce Labs links:

Test Files

Test files are housed in another repo.

Running make init will refresh the test_files submodule and get the files.


make test will run the node-based tests. To run the in-browser tests, clone the oss.sheetjs.com repo and replace the xlsx.js file (then fire up the browser and go to stress.html):

$ cp xlsx.js ../SheetJS.github.io
cd ../SheetJS.github.io
$ simplehttpserver # or "python -mSimpleHTTPServer" or "serve" 
$ open -a Chromium.app http://localhost:8000/stress.html

For a much smaller test, run make test_misc.


Due to the precarious nature of the Open Specifications Promise, it is very important to ensure code is cleanroom. Consult CONTRIBUTING.md

The xlsx.js file is constructed from the files in the bits subdirectory. The build script (run make) will concatenate the individual bits to produce the script. Before submitting a contribution, ensure that running make will produce the xlsx.js file exactly. The simplest way to test is to move the script:

$ mv xlsx.js xlsx.new.js
$ make
$ diff xlsx.js xlsx.new.js

To produce the dist files, run make dist. The dist files are updated in each version release and should not be committed between versions.


Please consult the attached LICENSE file for details. All rights not explicitly granted by the Apache 2.0 license are reserved by the Original Author.

It is the opinion of the Original Author that this code conforms to the terms of the Microsoft Open Specifications Promise, falling under the same terms as OpenOffice (which is governed by the Apache License v2). Given the vagaries of the promise, the Original Author makes no legal claim that in fact end users are protected from future actions. It is highly recommended that, for commercial uses, you consult a lawyer before proceeding.


ISO/IEC 29500:2012(E) "Information technology — Document description and processing languages — Office Open XML File Formats"

OSP-covered specifications:

  • [MS-XLSB]: Excel (.xlsb) Binary File Format
  • [MS-XLSX]: Excel (.xlsx) Extensions to the Office Open XML SpreadsheetML File Format
  • [MS-XLS]: Excel Binary File Format (.xls) Structure Specification
  • [MS-OLEDS]: Object Linking and Embedding (OLE) Data Structures
  • [MS-OLEPS]: Object Linking and Embedding (OLE) Property Set Data Structures

Open Document Format for Office Applications Version 1.2 (29 September 2011)


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