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0.0.2 • Public • Published


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Read, manipulate and write spreadsheet data and styles to XLSX and JSON.

Reverse engineered from Excel spreadsheet files as a project.



npm install exceljs

New Features!


Contributions are very welcome! It helps me know what features are desired or what bugs are causing the most pain.

I have just one request; If you submit a pull request for a bugfix, please add a unit-test or integration-test (in the spec folder) that catches the problem. Even a PR that just has a failing test is fine - I can analyse what the test is doing and fix the code from that.

Note: Please try to avoid modifying the package version in a PR. Versions are updated on release and any change will most likely result in merge collisions.

To be clear, all contributions added to this library will be included in the library's MIT licence.



const ExcelJS = require('exceljs');

ES5 Imports

To use the ES5 transpiled code, use the dist/es5 path.

const ExcelJS = require('exceljs/dist/es5');

Note: The ES5 build has an implicit dependency on a number of polyfills which are no longer explicitly added by exceljs. You will need to add "core-js" and "regenerator-runtime" to your dependencies and include the following requires in your code before the exceljs import:

// polyfills required by exceljs
// ...
const ExcelJS = require('exceljs/dist/es5');


ExcelJS publishes two browserified bundles inside the dist/ folder:

One with implicit dependencies on core-js polyfills...

<script src=""></script>
<script src="exceljs.js"></script>

And one without...

<script src="--your-project's-pollyfills-here--"></script>
<script src="exceljs.bare.js"></script>


Create a Workbook

var workbook = new Excel.Workbook();

Set Workbook Properties

workbook.creator = 'Me';
workbook.lastModifiedBy = 'Her';
workbook.created = new Date(1985, 8, 30);
workbook.modified = new Date();
workbook.lastPrinted = new Date(2016, 9, 27);
// Set workbook dates to 1904 date system = true;

Set Calculation Properties

// Force workbook calculation on load
workbook.calcProperties.fullCalcOnLoad = true;

Workbook Views

The Workbook views controls how many separate windows Excel will open when viewing the workbook.

workbook.views = [
    x: 0, y: 0, width: 10000, height: 20000,
    firstSheet: 0, activeTab: 1, visibility: 'visible'

Add a Worksheet

var sheet = workbook.addWorksheet('My Sheet');

Use the second parameter of the addWorksheet function to specify options for the worksheet.

For Example:

// create a sheet with red tab colour
var sheet = workbook.addWorksheet('My Sheet', {properties:{tabColor:{argb:'FFC0000'}}});
// create a sheet where the grid lines are hidden
var sheet = workbook.addWorksheet('My Sheet', {views: [{showGridLines: false}]});
// create a sheet with the first row and column frozen
var sheet = workbook.addWorksheet('My Sheet', {views:[{state: 'frozen', xSplit: 1, ySplit:1}]});

Remove a Worksheet

Use the worksheet id to remove the sheet from workbook.

For Example:

// Create a worksheet
var sheet = workbook.addWorksheet('My Sheet');
// Remove the worksheet using worksheet id

Access Worksheets

// Iterate over all sheets
// Note: workbook.worksheets.forEach will still work but this is better
workbook.eachSheet(function(worksheet, sheetId) {
  // ...
// fetch sheet by name
var worksheet = workbook.getWorksheet('My Sheet');
// fetch sheet by id
var worksheet = workbook.getWorksheet(1);

Worksheet State

// make worksheet visible
worksheet.state = 'visible';
// make worksheet hidden
worksheet.state = 'hidden';
// make worksheet hidden from 'hide/unhide' dialog
worksheet.state = 'veryHidden';

Worksheet Properties

Worksheets support a property bucket to allow control over some features of the worksheet.

// create new sheet with properties
var worksheet = workbook.addWorksheet('sheet', {properties:{tabColor:{argb:'FF00FF00'}}});
// create a new sheet writer with properties
var worksheetWriter = workbookWriter.addSheet('sheet', {properties:{outlineLevelCol:1}});
// adjust properties afterwards (not supported by worksheet-writer) = 2; = 15;

Supported Properties

Name Default Description
tabColor undefined Color of the tabs
outlineLevelCol 0 The worksheet column outline level
outlineLevelRow 0 The worksheet row outline level
defaultRowHeight 15 Default row height
defaultColWidth (optional) Default column width
dyDescent 55 TBD

Worksheet Metrics

Some new metrics have been added to Worksheet...

Name Description
rowCount The total row size of the document. Equal to the row number of the last row that has values.
actualRowCount A count of the number of rows that have values. If a mid-document row is empty, it will not be included in the count.
columnCount The total column size of the document. Equal to the maximum cell count from all of the rows
actualColumnCount A count of the number of columns that have values.

Page Setup

All properties that can affect the printing of a sheet are held in a pageSetup object on the sheet.

// create new sheet with pageSetup settings for A4 - landscape
var worksheet =  workbook.addWorksheet('sheet', {
  pageSetup:{paperSize: 9, orientation:'landscape'}
// create a new sheet writer with pageSetup settings for fit-to-page
var worksheetWriter = workbookWriter.addSheet('sheet', {
  pageSetup:{fitToPage: true, fitToHeight: 5, fitToWidth: 7}
// adjust pageSetup settings afterwards
worksheet.pageSetup.margins = {
  left: 0.7, right: 0.7,
  top: 0.75, bottom: 0.75,
  header: 0.3, footer: 0.3
// Set Print Area for a sheet
worksheet.pageSetup.printArea = 'A1:G20';
// Set multiple Print Areas by separating print areas with '&&'
worksheet.pageSetup.printArea = 'A1:G10&&A11:G20';
// Repeat specific rows on every printed page
worksheet.pageSetup.printTitlesRow = '1:3';
// Repeat specific columns on every printed page
worksheet.pageSetup.printTitlesColumn = 'A:C';

Supported pageSetup settings

Name Default Description
margins Whitespace on the borders of the page. Units are inches.
orientation 'portrait' Orientation of the page - i.e. taller (portrait) or wider (landscape)
horizontalDpi 4294967295 Horizontal Dots per Inch. Default value is -1
verticalDpi 4294967295 Vertical Dots per Inch. Default value is -1
fitToPage Whether to use fitToWidth and fitToHeight or scale settings. Default is based on presence of these settings in the pageSetup object - if both are present, scale wins (i.e. default will be false)
pageOrder 'downThenOver' Which order to print the pages - one of ['downThenOver', 'overThenDown']
blackAndWhite false Print without colour
draft false Print with less quality (and ink)
cellComments 'None' Where to place comments - one of ['atEnd', 'asDisplayed', 'None']
errors 'displayed' Where to show errors - one of ['dash', 'blank', 'NA', 'displayed']
scale 100 Percentage value to increase or reduce the size of the print. Active when fitToPage is false
fitToWidth 1 How many pages wide the sheet should print on to. Active when fitToPage is true
fitToHeight 1 How many pages high the sheet should print on to. Active when fitToPage is true
paperSize What paper size to use (see below)
showRowColHeaders false Whether to show the row numbers and column letters
showGridLines false Whether to show grid lines
firstPageNumber Which number to use for the first page
horizontalCentered false Whether to center the sheet data horizontally
verticalCentered false Whether to center the sheet data vertically

Example Paper Sizes

Name Value
Letter undefined
Legal 5
Executive 7
A4 9
A5 11
B5 (JIS) 13
Envelope #10 20
Envelope DL 27
Envelope C5 28
Envelope B5 34
Envelope Monarch 37
Double Japan Postcard Rotated 82
16K 197x273 mm 119

Headers and Footers

Here's how to add headers and footers. The added content is mainly text, such as time, introduction, file information, etc., and you can set the style of the text. In addition, you can set different texts for the first page and even page.

Note: Images are not currently supported.

// Set footer (default centered), result: "Page 2 of 16"
worksheet.headerFooter.oddFooter = "Page &P of &N";
// Set the footer (default centered) to bold, resulting in: "Page 2 of 16"
worksheet.headerFooter.oddFooter = "Page &P of &N";
// Set the left footer to 18px and italicize. Result: "Page 2 of 16"
worksheet.headerFooter.oddFooter = "&LPage &P of &N";
// Set the middle header to gray Aril, the result: "52 exceljs"
worksheet.headerFooter.oddHeader = "&C&KCCCCCC&\"Aril\"52 exceljs";
// Set the left, center, and right text of the footer. Result: “Exceljs” in the footer left. “demo.xlsx” in the footer center. “Page 2” in the footer right
worksheet.headerFooter.oddFooter = "&Lexceljs&C&F&RPage &P";
// Add different header & footer for the first page
worksheet.headerFooter.differentFirst = true;
worksheet.headerFooter.firstHeader = "Hello Exceljs";
worksheet.headerFooter.firstFooter = "Hello World"

Supported headerFooter settings

Name Default Description
differentFirst false Set the value of differentFirst as true, which indicates that headers/footers for first page are different from the other pages
differentOddEven false Set the value of differentOddEven as true, which indicates that headers/footers for odd and even pages are different
oddHeader null Set header string for odd(default) pages, could format the string
oddFooter null Set footer string for odd(default) pages, could format the string
evenHeader null Set header string for even pages, could format the string
evenFooter null Set footer string for even pages, could format the string
firstHeader null Set header string for the first page, could format the string
firstFooter null Set footer string for the first page, could format the string

Script Commands

Commands Description
&L Set position to the left
&C Set position to the center
&R Set position to the right
&P The current page number
&N The total number of pages
&D The current date
&T The current time
&G A picture
&A The worksheet name
&F The file name
&B Make text bold
&I Italicize text
&U Underline text
&"font name" font name, for example &"Aril"
&font size font size, for example 12
&KHEXCode font color, for example &KCCCCCC

Worksheet Views

Worksheets now support a list of views, that control how Excel presents the sheet:

  • frozen - where a number of rows and columns to the top and left are frozen in place. Only the bottom right section will scroll
  • split - where the view is split into 4 sections, each semi-independently scrollable.

Each view also supports various properties:

Name Default Description
state 'normal' Controls the view state - one of normal, frozen or split
rightToLeft false Sets the worksheet view's orientation to right-to-left
activeCell undefined The currently selected cell
showRuler true Shows or hides the ruler in Page Layout
showRowColHeaders true Shows or hides the row and column headers (e.g. A1, B1 at the top and 1,2,3 on the left
showGridLines true Shows or hides the gridlines (shown for cells where borders have not been defined)
zoomScale 100 Percentage zoom to use for the view
zoomScaleNormal 100 Normal zoom for the view
style undefined Presentation style - one of pageBreakPreview or pageLayout. Note pageLayout is not compatible with frozen views

Frozen Views

Frozen views support the following extra properties:

Name Default Description
xSplit 0 How many columns to freeze. To freeze rows only, set this to 0 or undefined
ySplit 0 How many rows to freeze. To freeze columns only, set this to 0 or undefined
topLeftCell special Which cell will be top-left in the bottom-right pane. Note: cannot be a frozen cell. Defaults to first unfrozen cell
worksheet.views = [
  {state: 'frozen', xSplit: 2, ySplit: 3, topLeftCell: 'G10', activeCell: 'A1'}

Split Views

Split views support the following extra properties:

Name Default Description
xSplit 0 How many points from the left to place the splitter. To split vertically, set this to 0 or undefined
ySplit 0 How many points from the top to place the splitter. To split horizontally, set this to 0 or undefined
topLeftCell undefined Which cell will be top-left in the bottom-right pane.
activePane undefined Which pane will be active - one of topLeft, topRight, bottomLeft and bottomRight
worksheet.views = [
  {state: 'split', xSplit: 2000, ySplit: 3000, topLeftCell: 'G10', activeCell: 'A1'}

Auto filters

It is possible to apply an auto filter to your worksheet.

worksheet.autoFilter = 'A1:C1';

While the range string is the standard form of the autoFilter, the worksheet will also support the following values:

// Set an auto filter from A1 to C1
worksheet.autoFilter = {
  from: 'A1',
  to: 'C1',
// Set an auto filter from the cell in row 3 and column 1
// to the cell in row 5 and column 12
worksheet.autoFilter = {
  from: {
    row: 3,
    column: 1
  to: {
    row: 5,
    column: 12
// Set an auto filter from D3 to the
// cell in row 7 and column 5
worksheet.autoFilter = {
  from: 'D3',
  to: {
    row: 7,
    column: 5


// Add column headers and define column keys and widths
// Note: these column structures are a workbook-building convenience only,
// apart from the column width, they will not be fully persisted.
worksheet.columns = [
  { header: 'Id', key: 'id', width: 10 },
  { header: 'Name', key: 'name', width: 32 },
  { header: 'D.O.B.', key: 'DOB', width: 10, outlineLevel: 1 }
// Access an individual columns by key, letter and 1-based column number
var idCol = worksheet.getColumn('id');
var nameCol = worksheet.getColumn('B');
var dobCol = worksheet.getColumn(3);
// set column properties
// Note: will overwrite cell value C1
dobCol.header = 'Date of Birth';
// Note: this will overwrite cell values C1:C2
dobCol.header = ['Date of Birth', 'A.K.A. D.O.B.'];
// from this point on, this column will be indexed by 'dob' and not 'DOB'
dobCol.key = 'dob';
dobCol.width = 15;
// Hide the column if you'd like
dobCol.hidden = true;
// set an outline level for columns
worksheet.getColumn(4).outlineLevel = 0;
worksheet.getColumn(5).outlineLevel = 1;
// columns support a readonly field to indicate the collapsed state based on outlineLevel
// iterate over all current cells in this column
dobCol.eachCell(function(cell, rowNumber) {
  // ...
// iterate over all current cells in this column including empty cells
dobCol.eachCell({ includeEmpty: true }, function(cell, rowNumber) {
  // ...
// add a column of new values
worksheet.getColumn(6).values = [1,2,3,4,5];
// add a sparse column of values
worksheet.getColumn(7).values = [,,2,3,,5,,7,,,,11];
// cut one or more columns (columns to the right are shifted left)
// If column properties have been defined, they will be cut or moved accordingly
// Known Issue: If a splice causes any merged cells to move, the results may be unpredictable
// remove one column and insert two more.
// Note: columns 4 and above will be shifted right by 1 column.
// Also: If the worksheet has more rows than values in the column inserts,
//  the rows will still be shifted as if the values existed
var newCol3Values = [1,2,3,4,5];
var newCol4Values = ['one', 'two', 'three', 'four', 'five'];
worksheet.spliceColumns(3, 1, newCol3Values, newCol4Values);


// Add a couple of Rows by key-value, after the last current row, using the column keys
worksheet.addRow({id: 1, name: 'John Doe', dob: new Date(1970,1,1)});
worksheet.addRow({id: 2, name: 'Jane Doe', dob: new Date(1965,1,7)});
// Add a row by contiguous Array (assign to columns A, B & C)
worksheet.addRow([3, 'Sam', new Date()]);
// Add a row by sparse Array (assign to columns A, E & I)
var rowValues = [];
rowValues[1] = 4;
rowValues[5] = 'Kyle';
rowValues[9] = new Date();
// Add an array of rows
var rows = [
  [5,'Bob',new Date()], // row by array
  {id:6, name: 'Barbara', dob: new Date()}
// Get a row object. If it doesn't already exist, a new empty one will be returned
var row = worksheet.getRow(5);
// Get the last editable row in a worksheet (or undefined if there are none)
var row = worksheet.lastRow;
// Set a specific row height
row.height = 42.5;
// make row hidden
row.hidden = true;
// set an outline level for rows
worksheet.getRow(4).outlineLevel = 0;
worksheet.getRow(5).outlineLevel = 1;
// rows support a readonly field to indicate the collapsed state based on outlineLevel
row.getCell(1).value = 5; // A5's value set to 5
row.getCell('name').value = 'Zeb'; // B5's value set to 'Zeb' - assuming column 2 is still keyed by name
row.getCell('C').value = new Date(); // C5's value set to now
// Get a row as a sparse array
// Note: interface change: worksheet.getRow(4) ==> worksheet.getRow(4).values
row = worksheet.getRow(4).values;
// assign row values by contiguous array (where array element 0 has a value)
row.values = [1,2,3];
// assign row values by sparse array  (where array element 0 is undefined)
var values = []
values[5] = 7;
values[10] = 'Hello, World!';
row.values = values;
expect(row.getCell(10).value).toEqual('Hello, World!');
// assign row values by object, using column keys
row.values = {
  id: 13,
  name: 'Thing 1',
  dob: new Date()
// Insert a page break below the row
// Iterate over all rows that have values in a worksheet
worksheet.eachRow(function(row, rowNumber) {
  console.log('Row ' + rowNumber + ' = ' + JSON.stringify(row.values));
// Iterate over all rows (including empty rows) in a worksheet
worksheet.eachRow({ includeEmpty: true }, function(row, rowNumber) {
  console.log('Row ' + rowNumber + ' = ' + JSON.stringify(row.values));
// Iterate over all non-null cells in a row
row.eachCell(function(cell, colNumber) {
  console.log('Cell ' + colNumber + ' = ' + cell.value);
// Iterate over all cells in a row (including empty cells)
row.eachCell({ includeEmpty: true }, function(cell, colNumber) {
  console.log('Cell ' + colNumber + ' = ' + cell.value);
// Cut one or more rows (rows below are shifted up)
// Known Issue: If a splice causes any merged cells to move, the results may be unpredictable
// remove one row and insert two more.
// Note: rows 4 and below will be shifted down by 1 row.
var newRow3Values = [1,2,3,4,5];
var newRow4Values = ['one', 'two', 'three', 'four', 'five'];
worksheet.spliceRows(3, 1, newRow3Values, newRow4Values);
// Cut one or more cells (cells to the right are shifted left)
// Note: this operation will not affect other rows
// remove one cell and insert two more (cells to the right of the cut cell will be shifted right)
row.splice(4,1,'new value 1', 'new value 2');
// Commit a completed row to stream
// row metrics
var rowSize = row.cellCount;
var numValues = row.actualCellCount;

Handling Individual Cells

var cell = worksheet.getCell('C3');
// Modify/Add individual cell
cell.value = new Date(1968, 5, 1);
// query a cell's type
// use string value of cell
myInput.value = cell.text;
// use html-safe string for rendering...
var html = '<div>' + cell.html + '</div>';

Merged Cells

// merge a range of cells
// ... merged cells are linked
worksheet.getCell('B5').value = 'Hello, World!';
// ... merged cells share the same style object
worksheet.getCell('B5').style.font = myFonts.arial;
// unmerging the cells breaks the style links
// merge by top-left, bottom-right
worksheet.mergeCells('K10', 'M12');
// merge by start row, start column, end row, end column (equivalent to K10:M12)

Duplicate a Row

duplicateRow(start, amount = 1, insert = true)
const wb = new ExcelJS.Workbook();
const ws = wb.addWorksheet('duplicateTest');
ws.getCell('A1').value = 'One';
ws.getCell('A2').value = 'Two';
ws.getCell('A3').value = 'Three';
ws.getCell('A4').value = 'Four';
// This line will duplicate the row 'One' twice but it will replace rows 'Two' and 'Three'
// if third param was true so it would insert 2 new rows with the values and styles of row 'One'
Parameter Description Default Value
start Row number you want to duplicate (first in excel is 1)
amount The times you want to duplicate the row 1
insert true if you want to insert new rows for the duplicates, or false if you want to replace them true

Defined Names

Individual cells (or multiple groups of cells) can have names assigned to them. The names can be used in formulas and data validation (and probably more).

// assign (or get) a name for a cell (will overwrite any other names that cell had)
worksheet.getCell('A1').name = 'PI';
// assign (or get) an array of names for a cell (cells can have more than one name)
worksheet.getCell('A1').names = ['thing1', 'thing2'];
expect(worksheet.getCell('A1').names).to.have.members(['thing1', 'thing2']);
// remove a name from a cell

Data Validations

Cells can define what values are valid or not and provide prompting to the user to help guide them.

Validation types can be one of the following:

Type Description
list Define a discrete set of valid values. Excel will offer these in a dropdown for easy entry
whole The value must be a whole number
decimal The value must be a decimal number
textLength The value may be text but the length is controlled
custom A custom formula controls the valid values

For types other than list or custom, the following operators affect the validation:

Operator Description
between Values must lie between formula results
notBetween Values must not lie between formula results
equal Value must equal formula result
notEqual Value must not equal formula result
greaterThan Value must be greater than formula result
lessThan Value must be less than formula result
greaterThanOrEqual Value must be greater than or equal to formula result
lessThanOrEqual Value must be less than or equal to formula result
// Specify list of valid values (One, Two, Three, Four).
// Excel will provide a dropdown with these values.
worksheet.getCell('A1').dataValidation = {
  type: 'list',
  allowBlank: true,
  formulae: ['"One,Two,Three,Four"']
// Specify list of valid values from a range.
// Excel will provide a dropdown with these values.
worksheet.getCell('A1').dataValidation = {
  type: 'list',
  allowBlank: true,
  formulae: ['$D$5:$F$5']
// Specify Cell must be a whole number that is not 5.
// Show the user an appropriate error message if they get it wrong
worksheet.getCell('A1').dataValidation = {
  type: 'whole',
  operator: 'notEqual',
  showErrorMessage: true,
  formulae: [5],
  errorStyle: 'error',
  errorTitle: 'Five',
  error: 'The value must not be Five'
// Specify Cell must be a decimal number between 1.5 and 7.
// Add 'tooltip' to help guid the user
worksheet.getCell('A1').dataValidation = {
  type: 'decimal',
  operator: 'between',
  allowBlank: true,
  showInputMessage: true,
  formulae: [1.5, 7],
  promptTitle: 'Decimal',
  prompt: 'The value must between 1.5 and 7'
// Specify Cell must be have a text length less than 15
worksheet.getCell('A1').dataValidation = {
  type: 'textLength',
  operator: 'lessThan',
  showErrorMessage: true,
  allowBlank: true,
  formulae: [15]
// Specify Cell must be have be a date before 1st Jan 2016
worksheet.getCell('A1').dataValidation = {
  type: 'date',
  operator: 'lessThan',
  showErrorMessage: true,
  allowBlank: true,
  formulae: [new Date(2016,0,1)]

Cell Comments

Add old style comment to a cell

// plain text note
worksheet.getCell('A1').note = 'Hello, ExcelJS!';
// colourful formatted note
ws.getCell('B1').note = {
  texts: [
    {'font': {'size': 12, 'color': {'theme': 0}, 'name': 'Calibri', 'family': 2, 'scheme': 'minor'}, 'text': 'This is '},
    {'font': {'italic': true, 'size': 12, 'color': {'theme': 0}, 'name': 'Calibri', 'scheme': 'minor'}, 'text': 'a'},
    {'font': {'size': 12, 'color': {'theme': 1}, 'name': 'Calibri', 'family': 2, 'scheme': 'minor'}, 'text': ' '},
    {'font': {'size': 12, 'color': {'argb': 'FFFF6600'}, 'name': 'Calibri', 'scheme': 'minor'}, 'text': 'colorful'},
    {'font': {'size': 12, 'color': {'theme': 1}, 'name': 'Calibri', 'family': 2, 'scheme': 'minor'}, 'text': ' text '},
    {'font': {'size': 12, 'color': {'argb': 'FFCCFFCC'}, 'name': 'Calibri', 'scheme': 'minor'}, 'text': 'with'},
    {'font': {'size': 12, 'color': {'theme': 1}, 'name': 'Calibri', 'family': 2, 'scheme': 'minor'}, 'text': ' in-cell '},
    {'font': {'bold': true, 'size': 12, 'color': {'theme': 1}, 'name': 'Calibri', 'family': 2, 'scheme': 'minor'}, 'text': 'format'},


Tables allow for in-sheet manipulation of tabular data.

To add a table to a worksheet, define a table model and call addTable:

// add a table to a sheet
  name: 'MyTable',
  ref: 'A1',
  headerRow: true,
  totalsRow: true,
  style: {
    theme: 'TableStyleDark3',
    showRowStripes: true,
  columns: [
    {name: 'Date', totalsRowLabel: 'Totals:', filterButton: true},
    {name: 'Amount', totalsRowFunction: 'sum', filterButton: false},
  rows: [
    [new Date('2019-07-20'), 70.10],
    [new Date('2019-07-21'), 70.60],
    [new Date('2019-07-22'), 70.10],

Note: Adding a table to a worksheet will modify the sheet by placing headers and row data to the sheet. Any data on the sheet covered by the resulting table (including headers and totals) will be overwritten.

Table Properties

The following table defines the properties supported by tables.

Table Property Description Required Default Value
name The name of the table Y
displayName The display name of the table N name
ref Top left cell of the table Y
headerRow Show headers at top of table N true
totalsRow Show totals at bottom of table N false
style Extra style properties N {}
columns Column definitions Y
rows Rows of data Y

Table Style Properties

The following table defines the properties supported within the table style property.

Style Property Description Required Default Value
theme The colour theme of the table N 'TableStyleMedium2'
showFirstColumn Highlight the first column (bold) N false
showLastColumn Highlight the last column (bold) N false
showRowStripes Alternate rows shown with background colour N false
showColumnStripes Alternate rows shown with background colour N false

Table Column Properties

The following table defines the properties supported within each table column.

Column Property Description Required Default Value
name The name of the column, also used in the header Y
filterButton Switches the filter control in the header N false
totalsRowLabel Label to describe the totals row (first column) N 'Total'
totalsRowFunction Name of the totals function N 'none'
totalsRowFormula Optional formula for custom functions N

Totals Functions

The following table list the valid values for the totalsRowFunction property defined by columns. If any value other than 'custom' is used, it is not necessary to include the associated formula as this will be inserted by the table.

Totals Functions Description
none No totals function for this column
average Compute average for the column
countNums Count the entries that are numbers
count Count of entries
max The maximum value in this column
min The minimum value in this column
stdDev The standard deviation for this column
var The variance for this column
sum The sum of entries for this column
custom A custom formula. Requires an associated totalsRowFormula value.

Table Style Themes

Valid theme names follow the following pattern:

  • "TableStyle[Shade][Number]"

Shades, Numbers can be one of:

  • Light, 1-21
  • Medium, 1-28
  • Dark, 1-11

For no theme, use the value null.

Note: custom table themes are not supported by exceljs yet.

Modifying Tables

Tables support a set of manipulation functions that allow data to be added or removed and some properties to be changed. Since many of these operations may have on-sheet effects, the changes must be committed once complete.

All index values in the table are zero based, so the first row number and first column number is 0.

Adding or Removing Headers and Totals

const table = ws.getTable('MyTable');
// turn header row on
table.headerRow = true;
// turn totals row off
table.totalsRow = false;
// commit the table changes into the sheet

Relocating a Table

const table = ws.getTable('MyTable');
// table top-left move to D4
table.ref = 'D4';
// commit the table changes into the sheet

Adding and Removing Rows

const table = ws.getTable('MyTable');
// remove first two rows
table.removeRows(0, 2);
// insert new rows at index 5
table.addRow([new Date('2019-08-05'), 5, 'Mid'], 5);
// append new row to bottom of table
table.addRow([new Date('2019-08-10'), 10, 'End']);
// commit the table changes into the sheet

Adding and Removing Columns

const table = ws.getTable('MyTable');
// remove second column
table.removeColumns(1, 1);
// insert new column (with data) at index 1
  {name: 'Letter', totalsRowFunction: 'custom', totalsRowFormula: 'ROW()', totalsRowResult: 6, filterButton: true},
  ['a', 'b', 'c', 'd'],
// commit the table changes into the sheet

Change Column Properties

const table = ws.getTable('MyTable');
// Get Column Wrapper for second column
const column = table.getColumn(1);
// set some properties = 'Code';
column.filterButton = true; = {font:{bold: true, name: 'Comic Sans MS'}};
column.totalsRowLabel = 'Totals';
column.totalsRowFunction = 'custom';
column.totalsRowFormula = 'ROW()';
column.totalsRowResult = 10;
// commit the table changes into the sheet


Cells, Rows and Columns each support a rich set of styles and formats that affect how the cells are displayed.

Styles are set by assigning the following properties:

// assign a style to a cell
ws.getCell('A1').numFmt = '0.00%';
// Apply styles to worksheet columns
ws.columns = [
  { header: 'Id', key: 'id', width: 10 },
  { header: 'Name', key: 'name', width: 32, style: { font: { name: 'Arial Black' } } },
  { header: 'D.O.B.', key: 'DOB', width: 10, style: { numFmt: 'dd/mm/yyyy' } }
// Set Column 3 to Currency Format
ws.getColumn(3).numFmt = '"£"#,##0.00;[Red]\-"£"#,##0.00';
// Set Row 2 to Comic Sans.
ws.getRow(2).font = { name: 'Comic Sans MS', family: 4, size: 16, underline: 'double', bold: true };

When a style is applied to a row or column, it will be applied to all currently existing cells in that row or column. Also, any new cell that is created will inherit its initial styles from the row and column it belongs to.

If a cell's row and column both define a specific style (e.g. font), the cell will use the row style over the column style. However if the row and column define different styles (e.g. column.numFmt and row.font), the cell will inherit the font from the row and the numFmt from the column.

Caveat: All the above properties (with the exception of numFmt, which is a string), are JS object structures. If the same style object is assigned to more than one spreadsheet entity, then each entity will share the same style object. If the style object is later modified before the spreadsheet is serialized, then all entities referencing that style object will be modified too. This behaviour is intended to prioritize performance by reducing the number of JS objects created. If you want the style objects to be independent, you will need to clone them before assigning them. Also, by default, when a document is read from file (or stream) if spreadsheet entities share similar styles, then they will reference the same style object too.

Number Formats

// display value as '1 3/5'
ws.getCell('A1').value = 1.6;
ws.getCell('A1').numFmt = '# ?/?';
// display value as '1.60%'
ws.getCell('B1').value = 0.016;
ws.getCell('B1').numFmt = '0.00%';


// for the wannabe graphic designers out there
ws.getCell('A1').font = {
  name: 'Comic Sans MS',
  family: 4,
  size: 16,
  underline: true,
  bold: true
// for the graduate graphic designers...
ws.getCell('A2').font = {
  name: 'Arial Black',
  color: { argb: 'FF00FF00' },
  family: 2,
  size: 14,
  italic: true
// for the vertical align
ws.getCell('A3').font = {
  vertAlign: 'superscript'
// note: the cell will store a reference to the font object assigned.
// If the font object is changed afterwards, the cell font will change also...
var font = { name: 'Arial', size: 12 };
ws.getCell('A3').font = font;
font.size = 20; // Cell A3 now has font size 20!
// Cells that share similar fonts may reference the same font object after
// the workbook is read from file or stream
Font Property Description Example Value(s)
name Font name. 'Arial', 'Calibri', etc.
family Font family for fallback. An integer value. 1 - Serif, 2 - Sans Serif, 3 - Mono, Others - unknown
scheme Font scheme. 'minor', 'major', 'none'
charset Font charset. An integer value. 1, 2, etc.
size Font size. An integer value. 9, 10, 12, 16, etc.
color Colour description, an object containing an ARGB value. { argb: 'FFFF0000'}
bold Font weight true, false
italic Font slope true, false
underline Font underline style true, false, 'none', 'single', 'double', 'singleAccounting', 'doubleAccounting'
strike Font strikethrough true, false
outline Font outline true, false
vertAlign Vertical align 'superscript', 'subscript'


// set cell alignment to top-left, middle-center, bottom-right
ws.getCell('A1').alignment = { vertical: 'top', horizontal: 'left' };
ws.getCell('B1').alignment = { vertical: 'middle', horizontal: 'center' };
ws.getCell('C1').alignment = { vertical: 'bottom', horizontal: 'right' };
// set cell to wrap-text
ws.getCell('D1').alignment = { wrapText: true };
// set cell indent to 1
ws.getCell('E1').alignment = { indent: 1 };
// set cell text rotation to 30deg upwards, 45deg downwards and vertical text
ws.getCell('F1').alignment = { textRotation: 30 };
ws.getCell('G1').alignment = { textRotation: -45 };
ws.getCell('H1').alignment = { textRotation: 'vertical' };

Valid Alignment Property Values

horizontal vertical wrapText shrinkToFit indent readingOrder textRotation
left top true true integer rtl 0 to 90
center middle false false ltr -1 to -90
right bottom vertical
fill distributed
justify justify


// set single thin border around A1
ws.getCell('A1').border = {
  top: {style:'thin'},
  left: {style:'thin'},
  bottom: {style:'thin'},
  right: {style:'thin'}
// set double thin green border around A3
ws.getCell('A3').border = {
  top: {style:'double', color: {argb:'FF00FF00'}},
  left: {style:'double', color: {argb:'FF00FF00'}},
  bottom: {style:'double', color: {argb:'FF00FF00'}},
  right: {style:'double', color: {argb:'FF00FF00'}}
// set thick red cross in A5
ws.getCell('A5').border = {
  diagonal: {up: true, down: true, style:'thick', color: {argb:'FFFF0000'}}

Valid Border Styles

  • thin
  • dotted
  • dashDot
  • hair
  • dashDotDot
  • slantDashDot
  • mediumDashed
  • mediumDashDotDot
  • mediumDashDot
  • medium
  • double
  • thick


// fill A1 with red darkVertical stripes
ws.getCell('A1').fill = {
  type: 'pattern',
// fill A2 with yellow dark trellis and blue behind
ws.getCell('A2').fill = {
  type: 'pattern',
// fill A3 with blue-white-blue gradient from left to right
ws.getCell('A3').fill = {
  type: 'gradient',
  gradient: 'angle',
  degree: 0,
  stops: [
    {position:0, color:{argb:'FF0000FF'}},
    {position:0.5, color:{argb:'FFFFFFFF'}},
    {position:1, color:{argb:'FF0000FF'}}
// fill A4 with red-green gradient from center
ws.getCell('A4').fill = {
  type: 'gradient',
  gradient: 'path',
  stops: [
    {position:0, color:{argb:'FFFF0000'}},
    {position:1, color:{argb:'FF00FF00'}}

Pattern Fills

Property Required Description
type Y Value: 'pattern'
Specifies this fill uses patterns
pattern Y Specifies type of pattern (see Valid Pattern Types below)
fgColor N Specifies the pattern foreground color. Default is black.
bgColor N Specifies the pattern background color. Default is white.

Valid Pattern Types

  • none
  • solid
  • darkGray
  • mediumGray
  • lightGray
  • gray125
  • gray0625
  • darkHorizontal
  • darkVertical
  • darkDown
  • darkUp
  • darkGrid
  • darkTrellis
  • lightHorizontal
  • lightVertical
  • lightDown
  • lightUp
  • lightGrid
  • lightTrellis

Gradient Fills

Property Required Description
type Y Value: 'gradient'
Specifies this fill uses gradients
gradient Y Specifies gradient type. One of ['angle', 'path']
degree angle For 'angle' gradient, specifies the direction of the gradient. 0 is from the left to the right. Values from 1 - 359 rotates the direction clockwise
center path For 'path' gradient. Specifies the relative coordinates for the start of the path. 'left' and 'top' values range from 0 to 1
stops Y Specifies the gradient colour sequence. Is an array of objects containing position and color starting with position 0 and ending with position 1. Intermediary positions may be used to specify other colours on the path.


Using the interface above it may be possible to create gradient fill effects not possible using the XLSX editor program. For example, Excel only supports angle gradients of 0, 45, 90 and 135. Similarly the sequence of stops may also be limited by the UI with positions [0,1] or [0,0.5,1] as the only options. Take care with this fill to be sure it is supported by the target XLSX viewers.

Rich Text

Individual cells now support rich text or in-cell formatting. Rich text values can control the font properties of any number of sub-strings within the text value. See Fonts for a complete list of details on what font properties are supported.

ws.getCell('A1').value = {
  'richText': [
    {'font': {'size': 12,'color': {'theme': 0},'name': 'Calibri','family': 2,'scheme': 'minor'},'text': 'This is '},
    {'font': {'italic': true,'size': 12,'color': {'theme': 0},'name': 'Calibri','scheme': 'minor'},'text': 'a'},
    {'font': {'size': 12,'color': {'theme': 1},'name': 'Calibri','family': 2,'scheme': 'minor'},'text': ' '},
    {'font': {'size': 12,'color': {'argb': 'FFFF6600'},'name': 'Calibri','scheme': 'minor'},'text': 'colorful'},
    {'font': {'size': 12,'color': {'theme': 1},'name': 'Calibri','family': 2,'scheme': 'minor'},'text': ' text '},
    {'font': {'size': 12,'color': {'argb': 'FFCCFFCC'},'name': 'Calibri','scheme': 'minor'},'text': 'with'},
    {'font': {'size': 12,'color': {'theme': 1},'name': 'Calibri','family': 2,'scheme': 'minor'},'text': ' in-cell '},
    {'font': {'bold': true,'size': 12,'color': {'theme': 1},'name': 'Calibri','family': 2,'scheme': 'minor'},'text': 'format'}
expect(ws.getCell('A1').text).to.equal('This is a colorful text with in-cell format');

Cell Protection

Cell level protection can be modified using the protection property.

ws.getCell('A1').protection = {
  locked: false,
  hidden: true,

Supported Protection Properties

Property Default Description
locked true Specifies whether a cell will be locked if the sheet is protected.
hidden false Specifies whether a cell's formula will be visible if the sheet is protected.

Conditional Formatting

Conditional formatting allows a sheet to show specific styles, icons, etc depending on cell values or any arbitrary formula.

Conditional formatting rules are added at the sheet level and will typically cover a range of cells.

Multiple rules can be applied to a given cell range and each rule will apply its own style.

If multiple rules affect a given cell, the rule priority value will determine which rule wins out if competing styles collide. The rule with the lower priority value wins. If priority values are not specified for a given rule, ExcelJS will assign them in ascending order.

Note: at present, only a subset of conditional formatting rules are supported. Specifically, only the formatting rules that do not require XML rendering inside an <extLst> element. This means that datasets and three specific icon sets (3Triangles, 3Stars, 5Boxes) are not supported.

// add a checkerboard pattern to A1:E7 based on row + col being even or odd
  ref: 'A1:E7',
  rules: [
      type: 'expression',
      formulae: ['MOD(ROW()+COLUMN(),2)=0'],
      style: {fill: {type: 'pattern', pattern: 'solid', bgColor: {argb: 'FF00FF00'}}},

Supported Conditional Formatting Rule Types

Type Description
expression Any custom function may be used to activate the rule.
cellIs Compares cell value with supplied formula using specified operator
top10 Applies formatting to cells with values in top (or bottom) ranges
aboveAverage Applies formatting to cells with values above (or below) average
colorScale Applies a coloured background to cells based on where their values lie in the range
iconSet Adds one of a range of icons to cells based on value
containsText Applies formatting based on whether cell a specific text
timePeriod Applies formatting based on whether cell datetime value lies within a specified range


Field Optional Default Description
type 'expression'
priority Y <auto> determines priority ordering of styles
formulae array of 1 formula string that returns a true/false value. To reference the cell value, use the top-left cell address
style style structure to apply if the formula returns true

Cell Is

Field Optional Default Description
type 'cellIs'
priority Y <auto> determines priority ordering of styles
operator how to compare cell value with formula result
formulae array of 1 formula string that returns the value to compare against each cell
style style structure to apply if the comparison returns true

Cell Is Operators

Operator Description
equal Apply format if cell value equals formula value
greaterThan Apply format if cell value is greater than formula value
lessThan Apply format if cell value is less than formula value
between Apply format if cell value is between two formula values (inclusive)

Top 10

Field Optional Default Description
type 'top10'
priority Y <auto> determines priority ordering of styles
rank Y 10 specifies how many top (or bottom) values are included in the formatting
percent Y false if true, the rank field is a percentage, not an absolute
bottom Y false if true, the bottom values are included instead of the top
style style structure to apply if the comparison returns true

Above Average

Field Optional Default Description
type 'aboveAverage'
priority Y <auto> determines priority ordering of styles
aboveAverage Y false if true, the rank field is a percentage, not an absolute
style style structure to apply if the comparison returns true

Colour Scale

Field Optional Default Description
type 'colorScale'
priority Y <auto> determines priority ordering of styles
cfvo array of 2 to 5 Conditional Formatting Value Objects specifying way-points in the value range
color corresponding array of colours to use at given way points
style style structure to apply if the comparison returns true

Icon Set

Field Optional Default Description
type 'iconSet'
priority Y <auto> determines priority ordering of styles
iconSet Y 3TrafficLights name of icon set to use
cfvo array of 2 to 5 Conditional Formatting Value Objects specifying way-points in the value range
style style structure to apply if the comparison returns true

Contains Text

Field Optional Default Description
type 'containsText'
priority Y <auto> determines priority ordering of styles
operator type of text comparison
text text to search for
style style structure to apply if the comparison returns true

Contains Text Operators

Operator Description
containsText Apply format if cell value contains the value specified in the 'text' field
containsBlanks Apply format if cell value contains blanks
notContainsBlanks Apply format if cell value does not contain blanks
containsErrors Apply format if cell value contains errors
notContainsErrors Apply format if cell value does not contain errors

Time Period

Field Optional Default Description
type 'timePeriod'
priority Y <auto> determines priority ordering of styles
timePeriod what time period to compare cell value to
style style structure to apply if the comparison returns true

Time Periods

Time Period Description
lastWeek Apply format if cell value falls within the last week
thisWeek Apply format if cell value falls in this week
nextWeek Apply format if cell value falls in the next week
yesterday Apply format if cell value is equal to yesterday
today Apply format if cell value is equal to today
tomorrow Apply format if cell value is equal to tomorrow
last7Days Apply format if cell value falls within the last 7 days
lastMonth Apply format if cell value falls in last month
thisMonth Apply format if cell value falls in this month
nextMonth Apply format if cell value falls in next month

Outline Levels

Excel supports outlining; where rows or columns can be expanded or collapsed depending on what level of detail the user wishes to view.

Outline levels can be defined in column setup:

worksheet.columns = [
  { header: 'Id', key: 'id', width: 10 },
  { header: 'Name', key: 'name', width: 32 },
  { header: 'D.O.B.', key: 'DOB', width: 10, outlineLevel: 1 }

Or directly on the row or column

worksheet.getColumn(3).outlineLevel = 1;
worksheet.getRow(3).outlineLevel = 1;

The sheet outline levels can be set on the worksheet

// set column outline level = 1;
// set row outline level = 1;

Note: adjusting outline levels on rows or columns or the outline levels on the worksheet will incur a side effect of also modifying the collapsed property of all rows or columns affected by the property change. E.g.: = 1;
worksheet.getColumn(3).outlineLevel = 1;
expect(worksheet.getColumn(3).collapsed); = 2;

The outline properties can be set on the worksheet = {
  summaryBelow: false,
  summaryRight: false,


Adding images to a worksheet is a two-step process. First, the image is added to the workbook via the addImage() function which will also return an imageId value. Then, using the imageId, the image can be added to the worksheet either as a tiled background or covering a cell range.

Note: As of this version, adjusting or transforming the image is not supported.

Add Image to Workbook

The Workbook.addImage function supports adding images by filename or by Buffer. Note that in both cases, the extension must be specified. Valid extension values include 'jpeg', 'png', 'gif'.

// add image to workbook by filename
var imageId1 = workbook.addImage({
  filename: 'path/to/image.jpg',
  extension: 'jpeg',
// add image to workbook by buffer
var imageId2 = workbook.addImage({
  buffer: fs.readFileSync('path/to.image.png'),
  extension: 'png',
// add image to workbook by base64
var myBase64Image = "data:image/png;base64,iVBORw0KG...";
var imageId2 = workbook.addImage({
  base64: myBase64Image,
  extension: 'png',

Add image background to worksheet

Using the image id from Workbook.addImage, the background to a worksheet can be set using the addBackgroundImage function

// set background

Add image over a range

Using the image id from Workbook.addImage, an image can be embedded within the worksheet to cover a range. The coordinates calculated from the range will cover from the top-left of the first cell to the bottom right of the second.

// insert an image over B2:D6
worksheet.addImage(imageId2, 'B2:D6');

Using a structure instead of a range string, it is possible to partially cover cells.

Note that the coordinate system used for this is zero based, so the top-left of A1 will be { col: 0, row: 0 }. Fractions of cells can be specified by using floating point numbers, e.g. the midpoint of A1 is { col: 0.5, row: 0.5 }.

// insert an image over part of B2:D6
worksheet.addImage(imageId2, {
  tl: { col: 1.5, row: 1.5 },
  br: { col: 3.5, row: 5.5 }

The cell range can also have the property 'editAs' which will control how the image is anchored to the cell(s) It can have one of the following values:

Value Description
undefined It specifies the image will be moved and sized with cells
oneCell This is the default. Image will be moved with cells but not sized
absolute Image will not be moved or sized with cells
ws.addImage(imageId, {
  tl: { col: 0.1125, row: 0.4 },
  br: { col: 2.101046875, row: 3.4 },
  editAs: 'oneCell'

Add image to a cell

You can add an image to a cell and then define its width and height in pixels at 96dpi.

worksheet.addImage(imageId2, {
  tl: { col: 0, row: 0 },
  ext: { width: 500, height: 200 }

Add image with hyperlinks

You can add an image with hyperlinks to a cell, and defines the hyperlinks in image range.

worksheet.addImage(imageId2, {
  tl: { col: 0, row: 0 },
  ext: { width: 500, height: 200 },
  hyperlinks: {
    hyperlink: '',
    tooltip: ''

Sheet Protection

Worksheets can be protected from modification by adding a password.

await worksheet.protect('the-password', options);

Worksheet protection can also be removed:


See Cell Protection for details on how to modify individual cell protection.

Note: While the protect() function returns a Promise indicating that it is async, the current implementation runs on the main thread and will use approx 600ms on an average CPU.

Sheet Protection Options

Field Default Description
selectLockedCells true Lets the user select locked cells
selectUnlockedCells true Lets the user select unlocked cells
formatCells false Lets the user format cells
formatColumns false Lets the user format columns
formatRows false Lets the user format rows
insertRows false Lets the user insert rows
insertColumns false Lets the user insert columns
insertHyperlinks false Lets the user insert hyperlinks
deleteRows false Lets the user delete rows
deleteColumns false Lets the user delete columns
sort false Lets the user sort data
autoFilter false Lets the user filter data in tables
pivotTables false Lets the user use pivot tables

File I/O


Reading XLSX

// read from a file
var workbook = new Excel.Workbook();
  .then(function() {
    // use workbook
// pipe from stream
var workbook = new Excel.Workbook();
// load from buffer
var workbook = new Excel.Workbook();
  .then(function() {
    // use workbook

Writing XLSX

// write to a file
var workbook = createAndFillWorkbook();
  .then(function() {
    // done
// write to a stream
  .then(function() {
    // done
// write to a new buffer
  .then(function(buffer) {
    // done


Reading CSV

// read from a file
var workbook = new Excel.Workbook();
  .then(worksheet => {
    // use workbook or worksheet
// read from a stream
var workbook = new Excel.Workbook();
  .then(worksheet => {
    // use workbook or worksheet
// pipe from stream
var workbook = new Excel.Workbook();
// read from a file with European Dates
var workbook = new Excel.Workbook();
var options = {
  dateFormats: ['DD/MM/YYYY']
workbook.csv.readFile(filename, options)
  .then(worksheet => {
    // use workbook or worksheet
// read from a file with custom value parsing
var workbook = new Excel.Workbook();
var options = {
  map(value, index) {
    switch(index) {
      case 0:
        // column 1 is string
        return value;
      case 1:
        // column 2 is a date
        return new Date(value);
      case 2:
        // column 3 is JSON of a formula value
        return JSON.parse(value);
        // the rest are numbers
        return parseFloat(value);
workbook.csv.readFile(filename, options)
  .then(function(worksheet) {
    // use workbook or worksheet

The CSV parser uses fast-csv to read the CSV file. The options passed into the read functions above is also passed to fast-csv for parsing of the csv data. Please refer to the fast-csv for details.

Dates are parsed using the npm module dayjs. If a dateFormats array is not supplied, the following dateFormats are used:

  • 'YYYY-MM-DD[T]HH:mm:ss'
  • 'MM-DD-YYYY'
  • 'YYYY-MM-DD'

Please refer to the dayjs CustomParseFormat plugin for details on how to structure a dateFormat.

Writing CSV

// write to a file
var workbook = createAndFillWorkbook();
  .then(() => {
    // done
// write to a stream
// Be careful that you need to provide sheetName or
// sheetId for correct import to csv.
workbook.csv.write(stream, { sheetName: 'Page name' })
  .then(() => {
    // done
// write to a file with European Date-Times
var workbook = new Excel.Workbook();
var options = {
  dateFormat: 'DD/MM/YYYY HH:mm:ss',
  dateUTC: true, // use utc when rendering dates
workbook.csv.writeFile(filename, options)
  .then(() => {
    // done
// write to a file with custom value formatting
var workbook = new Excel.Workbook();
var options = {
  map(value, index) {
    switch(index) {
      case 0:
        // column 1 is string
        return value;
      case 1:
        // column 2 is a date
        return moment(value).format('YYYY-MM-DD');
      case 2:
        // column 3 is a formula, write just the result
        return value.result;
        // the rest are numbers
        return value;
workbook.csv.writeFile(filename, options)
  .then(() => {
    // done
// write to a new buffer
  .then(function(buffer) {
    // done

The CSV parser uses fast-csv to write the CSV file. The options passed into the write functions above is also passed to fast-csv for writing the csv data. Please refer to the fast-csv for details.

Dates are formatted using the npm module moment. If no dateFormat is supplied, moment.ISO_8601 is used. When writing a CSV you can supply the boolean dateUTC as true to have ExcelJS parse the date without automatically converting the timezone using moment.utc().

Streaming I/O

The File I/O documented above requires that an entire workbook is built up in memory before the file can be written. While convenient, it can limit the size of the document due to the amount of memory required.

A streaming writer (or reader) processes the workbook or worksheet data as it is generated, converting it into file form as it goes. Typically this is much more efficient on memory as the final memory footprint and even intermediate memory footprints are much more compact than with the document version, especially when you consider that the row and cell objects are disposed once they are committed.

The interface to the streaming workbook and worksheet is almost the same as the document versions with a few minor practical differences:

  • Once a worksheet is added to a workbook, it cannot be removed.
  • Once a row is committed, it is no longer accessible since it will have been dropped from the worksheet.
  • unMergeCells() is not supported.

Note that it is possible to build the entire workbook without committing any rows. When the workbook is committed, all added worksheets (including all uncommitted rows) will be automatically committed. However in this case, little will have been gained over the Document version.

Streaming XLSX

Streaming XLSX Writer

The streaming XLSX writer is available in the namespace.

The constructor takes an optional options object with the following fields:

Field Description
stream Specifies a writable stream to write the XLSX workbook to.
filename If stream not specified, this field specifies the path to a file to write the XLSX workbook to.
useSharedStrings Specifies whether to use shared strings in the workbook. Default is false
useStyles Specifies whether to add style information to the workbook. Styles can add some performance overhead. Default is false
zip Zip options that ExcelJS internally passes to Archiver. Default is undefined

If neither stream nor filename is specified in the options, the workbook writer will create a StreamBuf object that will store the contents of the XLSX workbook in memory. This StreamBuf object, which can be accessed via the property, can be used to either access the bytes directly by or to pipe the contents to another stream.

// construct a streaming XLSX workbook writer with styles and shared strings
var options = {
  filename: './streamed-workbook.xlsx',
  useStyles: true,
  useSharedStrings: true
var workbook = new;

In general, the interface to the streaming XLSX writer is the same as the Document workbook (and worksheets) described above, in fact the row, cell and style objects are the same.

However there are some differences...


As seen above, the WorkbookWriter will typically require the output stream or file to be specified in the constructor.

Committing Data

When a worksheet row is ready, it should be committed so that the row object and contents can be freed. Typically this would be done as each row is added...

   id: i,
   name: theName,
   etc: someOtherDetail

The reason the WorksheetWriter does not commit rows as they are added is to allow cells to be merged across rows:

worksheet.getCell('A1').value = 'I am merged';
worksheet.getCell('C1').value = 'I am not';
worksheet.getCell('C2').value = 'Neither am I';
worksheet.getRow(2).commit(); // now rows 1 and two are committed.

As each worksheet is completed, it must also be committed:

// Finished adding data. Commit the worksheet

To complete the XLSX document, the workbook must be committed. If any worksheet in a workbook are uncommitted, they will be committed automatically as part of the workbook commit.

// Finished the workbook.
  .then(function() {
    // the stream has been written


A portion of this library has been isolated and tested for use within a browser environment.

Due to the streaming nature of the workbook reader and workbook writer, these have not been included. Only the document based workbook may be used (see Create a Workbook for details).

For example code using ExcelJS in the browser take a look at the spec/browser folder in the github repo.


The following files are pre-bundled and included inside the dist folder.

  • exceljs.js
  • exceljs.min.js

Value Types

The following value types are supported.

Null Value

Enum: Excel.ValueType.Null

A null value indicates an absence of value and will typically not be stored when written to file (except for merged cells). It can be used to remove the value from a cell.


worksheet.getCell('A1').value = null;

Merge Cell

Enum: Excel.ValueType.Merge

A merge cell is one that has its value bound to another 'master' cell. Assigning to a merge cell will cause the master's cell to be modified.

Number Value

Enum: Excel.ValueType.Number

A numeric value.


worksheet.getCell('A1').value = 5;
worksheet.getCell('A2').value = 3.14159;

String Value

Enum: Excel.ValueType.String

A simple text string.


worksheet.getCell('A1').value = 'Hello, World!';

Date Value

Enum: Excel.ValueType.Date

A date value, represented by the JavaScript Date type.


worksheet.getCell('A1').value = new Date(2017, 2, 15);

Hyperlink Value

Enum: Excel.ValueType.Hyperlink

A URL with both text and link value.


// link to web
worksheet.getCell('A1').value = {
  text: '',
  hyperlink: '',
  tooltip: ''
// internal link
worksheet.getCell('A1').value = { text: 'Sheet2', hyperlink: '#\'Sheet2\'!A1' };

Formula Value

Enum: Excel.ValueType.Formula

An Excel formula for calculating values on the fly. Note that while the cell type will be Formula, the cell may have an effectiveType value that will be derived from the result value.

Note that ExcelJS cannot process the formula to generate a result, it must be supplied.


worksheet.getCell('A3').value = { formula: 'A1+A2', result: 7 };

Cells also support convenience getters to access the formula and result:

worksheet.getCell('A3').formula === 'A1+A2';
worksheet.getCell('A3').result === 7;

Shared Formula

Shared formulae enhance the compression of the xlsx document by decreasing the repetition of text within the worksheet xml. The top-left cell in a range is the designated master and will hold the formula that all the other cells in the range will derive from. The other 'slave' cells can then refer to this master cell instead of redefining the whole formula again. Note that the master formula will be translated to the slave cells in the usual Excel fashion so that references to other cells will be shifted down and to the right depending on the slave's offset to the master. For example: if the master cell A2 has a formula referencing A1 then if cell B2 shares A2's formula, then it will reference B1.

A master formula can be assigned to a cell along with the slave cells in its range

worksheet.getCell('A2').value = {
  formula: 'A1',
  result: 10,
  shareType: 'shared',
  ref: 'A2:B3'

A shared formula can be assigned to a cell using a new value form:

worksheet.getCell('B2').value = { sharedFormula: 'A2', result: 10 };

This specifies that the cell B2 is a formula that will be derived from the formula in A2 and its result is 10.

The formula convenience getter will translate the formula in A2 to what it should be in B2:


Shared formulae can be assigned into a sheet using the 'fillFormula' function:

// set A1 to starting number
worksheet.getCell('A1').value = 1;
// fill A2 to A10 with ascending count starting from A1
worksheet.fillFormula('A2:A10', 'A1+1', [2,3,4,5,6,7,8,9,10]);

fillFormula can also use a callback function to calculate the value at each cell

// fill A2 to A100 with ascending count starting from A1
worksheet.fillFormula('A2:A100', 'A1+1', (row, col) => row);

Formula Type

To distinguish between real and translated formula cells, use the formulaType getter:

worksheet.getCell('A3').formulaType === Enums.FormulaType.Master;
worksheet.getCell('B3').formulaType === Enums.FormulaType.Shared;

Formula type has the following values:

Name Value
Enums.FormulaType.None 0
Enums.FormulaType.Master 1
Enums.FormulaType.Shared 2

Array Formula

A new way of expressing shared formulae in Excel is the array formula. In this form, the master cell is the only cell that contains any information relating to a formula. It contains the shareType 'array' along with the range of cells it applies to and the formula that will be copied. The rest of the cells are regular cells with regular values.

Note: array formulae are not translated in the way shared formulae are. So if master cell A2 refers to A1, then slave cell B2 will also refer to A1.


// assign array formula to A2:B3
worksheet.getCell('A2').value = {
  formula: 'A1',
  result: 10,
  shareType: 'array',
  ref: 'A2:B3'
// it may not be necessary to fill the rest of the values in the sheet

The fillFormula function can also be used to fill an array formula

// fill A2:B3 with array formula "A1"
worksheet.fillFormula('A2:B3', 'A1', [1,1,1,1], 'array');

Rich Text Value

Enum: Excel.ValueType.RichText

Rich, styled text.


worksheet.getCell('A1').value = {
  richText: [
    { text: 'This is '},
    {font: {italic: true}, text: 'italic'},

Boolean Value

Enum: Excel.ValueType.Boolean


worksheet.getCell('A1').value = true;
worksheet.getCell('A2').value = false;

Error Value

Enum: Excel.ValueType.Error


worksheet.getCell('A1').value = { error: '#N/A' };
worksheet.getCell('A2').value = { error: '#VALUE!' };

The current valid Error text values are:

Name Value
Excel.ErrorValue.NotApplicable #N/A
Excel.ErrorValue.Ref #REF!
Excel.ErrorValue.Name #NAME?
Excel.ErrorValue.DivZero #DIV/0!
Excel.ErrorValue.Null #NULL!
Excel.ErrorValue.Value #VALUE!
Excel.ErrorValue.Num #NUM!

Interface Changes

Every effort is made to make a good consistent interface that doesn't break through the versions but regrettably, now and then some things have to change for the greater good.



The arguments in the callback function to Worksheet.eachRow have been swapped and changed; it was function(rowNumber,rowValues), now it is function(row, rowNumber) which gives it a look and feel more like the underscore (_.each) function and priorities the row object over the row number.


This function has changed from returning a sparse array of cell values to returning a Row object. This enables accessing row properties and will facilitate managing row styles and so on.

The sparse array of cell values is still available via Worksheet.getRow(rowNumber).values;



cell.styles renamed to


Promises returned from functions switched from Bluebird to native node Promise which can break calling code if they rely on Bluebird's extra features.

To mitigate this the following two changes were added to 0.3.0:

  • A more fully featured and still browser compatible promise lib is used by default. This lib supports many of the features of Bluebird but with a much lower footprint.
  • An option to inject a different Promise implementation. See Config section for more details.


ExcelJS now supports dependency injection for the promise library. You can restore Bluebird promises by including the following code in your module...

ExcelJS.config.setValue('promise', require('bluebird'));

Please note: I have tested ExcelJS with bluebird specifically (since up until recently this was the library it used). From the tests I have done it will not work with Q.


Dist Folder

Before publishing this module, the source code is transpiled and otherwise processed before being placed in a dist/ folder. This README identifies two files - a browserified bundle and minified version. No other contents of the dist/ folder are guaranteed in any way other than the file specified as "main" in the package.json

Known Issues

Testing with Puppeteer

The test suite included in this lib includes a small script executed in a headless browser to validate the bundled packages. At the time of this writing, it appears that this test does not play nicely in the Windows Linux subsystem.

For this reason, the browser test can be disabled by the existence of a file named .disable-test-browser

sudo apt-get install libfontconfig

Splice vs Merge

If any splice operation affects a merged cell, the merge group will not be moved correctly

Release History

Version Changes
  • Bug Fixes
    • More textual data written properly to xml (including text, hyperlinks, formula results and format codes)
    • Better date format code recognition
  • Cell Font Style
  • Fixed potential race condition on zip write
  • Bug Fixes
    • Now handles 10 or more worksheets in one workbook
    • theme1.xml file properly added and referenced
  • Cell Borders
  • Bug Fixes
    • More compatible theme1.xml included in XLSX file
  • Cell Fills
  • Bug Fixes
    • More compatible theme1.xml included in XLSX file
    • Fixed filename case issue
  • Cell Fills
  • Bug Fixes
    • Added docProps files to satisfy Mac Excel users
    • Fixed filename case issue
    • Fixed worksheet id issue
  • Core Workbook Properties
  • Bug Fixes
    • Handles File Not Found error
  • CSV Files
  • Streaming XLSX Writer
    • At long last ExcelJS can support writing massive XLSX files in a scalable memory efficient manner. Performance has been optimised and even smaller spreadsheets can be faster to write than the document writer. Options have been added to control the use of shared strings and styles as these can both have a considerable effect on performance
  • Worksheet.lastRow
    • Access the last editable row in a worksheet.
  • Row.commit()
    • For streaming writers, this method commits the row (and any previous rows) to the stream. Committed rows will no longer be editable (and are typically deleted from the worksheet object). For Document type workbooks, this method has no effect.
  • One Billion Cells
    • Achievement Unlocked: A simple test using ExcelJS has created a spreadsheet with 1,000,000,000 cells. Made using random data with 100,000,000 rows of 10 cells per row. I cannot validate the file yet as Excel will not open it and I have yet to implement the streaming reader but I have every confidence that it is good since 1,000,000 rows loads ok.
  • Bug Fixes
  • Streaming XLSX Writer
    • At long last ExcelJS can support writing massive XLSX files in a scalable memory efficient manner. Performance has been optimised and even smaller spreadsheets can be faster to write than the document writer. Options have been added to control the use of shared strings and styles as these can both have a considerable effect on performance
  • Worksheet.lastRow
    • Access the last editable row in a worksheet.
  • Row.commit()
    • For streaming writers, this method commits the row (and any previous rows) to the stream. Committed rows will no longer be editable (and are typically deleted from the worksheet object). For Document type workbooks, this method has no effect.
  • Data Validations
    • Cells can now define validations that controls the valid values the cell can have
  • Fixed "read property 'richText' of undefined error. Thanks to james075
  • Refactoring Complete. All unit and integration tests pass.
  • Merged Fall back to JSON.stringify() if unknown Cell.Type #137 with some modification. If a cell value is assigned to an unrecognisable javascript object, the stored value in xlsx and csv files will be JSON stringified. Note that if the file is read again, no attempt will be made to parse the stringified JSON text. Thanks to wulfsolter for the contribution.
  • Merged Protect cell fix #166. This does not mean full support for protected cells merely that the parser is not confused by the extra xml. Thanks to jayflo for the contribution.
  • Added functions to delete cells, rows and columns from a worksheet. Modelled after the Array splice method, the functions allow cells, rows and columns to be deleted (and optionally inserted). See Columns and Rows for details.
    Note: Not compatible with cell merges
  • Merged Fix issue #178 #201. Adds the following properties to workbook:
    • title
    • subject
    • keywords
    • category
    • description
    • company
    • manager
    Thanks to stavenko for the contribution.
  • Browser Compatible!
    • Well mostly. I have added a browser sub-folder that contains a browserified bundle and an index.js that can be used to generate another. See Browser section for details.
  • Fixed corrupted theme.xml. Apologies for letting that through.
  • Merged [BUGFIX] data validation formulae undefined #253. Thanks to jayflo for the contribution.
  • Reduced Dependencies.
    • Goodbye lodash, goodbye bluebird. Minified bundle is now just over half what it was in the first version.
  • Addressed the following issues:

    These issues are potentially caused by a bug that caused colours with zero themes, tints or indexes to be rendered and parsed incorrectly.

    Regarding themes: the theme files stored inside the xlsx container hold important information regarding colours, styles etc and if the theme information from a loaded xlsx file is lost, the results can be unpredictable and undesirable. To address this, when an ExcelJS Workbook parses an XLSX file, it will preserve any theme files it finds and include them when writing to a new XLSX. If this behaviour is not desired, the Workbook class exposes a clearThemes() function which will drop the theme content. Note that this behaviour is only implemented in the document based Workbook class, not the streamed Reader and Writer.

  • Switching to transpiled code for distribution. This will ensure compatability with 4.0.0 and above from here on. And it will also allow use of much more expressive JS code in the lib folder!
  • Basic Image Support!Images can now be added to worksheets either as a tiled background or stretched over a range. Note: other features like rotation, etc. are not supported yet and will reqeuire further work.

Major Version Change

Introducing async/await to ExcelJS!

The new async and await features of JavaScript can help a lot to make code more readable and maintainable. To avoid confusion, particularly with returned promises from async functions, we have had to remove the Promise class configuration option and from v2 onwards ExcelJS will use native Promises. Since this is potentially a breaking change we're bumping the major version for this release.



Another Major Version Change

Javascript has changed a lot over the years, and so have the modules and technologies surrounding it. To this end, this major version of ExcelJS changes the structure of the publish artefacts:

Main Export is now the Original Javascript Source

Prior to this release, the transpiled ES5 code was exported as the package main. From now on, the package main comes directly from the lib/ folder. This means a number of dependencies have been removed, including the polyfills.

ES5 and Browserify are Still Included

In order to support those that still require ES5 ready code (e.g. as dependencies in web apps) the source code will still be transpiled and available in dist/es5.

The ES5 code is also browserified and available as dist/exceljs.js or dist/exceljs.min.js

See the section Importing for details

  • Conditional Formatting A subset of Excel Conditional formatting has been implemented! Specifically the formatting rules that do not require XML to be rendered inside an <extLst> node, or in other words everything except databar and three icon sets (3Triangles, 3Stars, 5Boxes). These will be implemented in due course
  • Merged remove core-js/ import #1030. Many thanks to jeffrey n. carre for this contribution. This change is used to create a new browserified bundle artefact that does not include any polyfills. See Browserify for details.


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