sheetjs/docbits/81_writeopts.md

Writing Options

The exported write and writeFile functions accept an options argument:

Option Name	Default	Description
type		Output data encoding (see Output Type below)
cellDates	false	Store dates as type d (default is n)
bookSST	false	Generate Shared String Table **
bookType	"xlsx"	Type of Workbook (see below for supported formats)
sheet	""	Name of Worksheet for single-sheet formats **
compression	false	Use ZIP compression for ZIP-based formats **
Props		Override workbook properties when writing **
themeXLSX		Override theme XML when writing XLSX/XLSB/XLSM **
ignoreEC	true	Suppress "number as text" errors **

• bookSST is slower and more memory intensive, but has better compatibility with older versions of iOS Numbers
• The raw data is the only thing guaranteed to be saved. Features not described in this README may not be serialized.
• 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 error in the presence of dates.
• Props is an object mirroring the workbook Props field. See the table from the Workbook File Properties section.
• if specified, the string from themeXLSX will be saved as the primary theme for XLSX/XLSB/XLSM files (to xl/theme/theme1.xml in the ZIP)
• Due to a bug in the program, some features like "Text to Columns" will crash Excel on worksheets where error conditions are ignored. The writer will mark files to ignore the error by default. Set ignoreEC to false to suppress.

Supported Output Formats

For broad compatibility with third-party tools, this library supports many output formats. The specific file type is controlled with bookType option:

bookType	file ext	container	sheets	Description
xlsx	.xlsx	ZIP	multi	Excel 2007+ XML Format
xlsm	.xlsm	ZIP	multi	Excel 2007+ Macro XML Format
xlsb	.xlsb	ZIP	multi	Excel 2007+ Binary Format
biff8	.xls	CFB	multi	Excel 97-2004 Workbook Format
biff5	.xls	CFB	multi	Excel 5.0/95 Workbook Format
biff4	.xls	none	single	Excel 4.0 Worksheet Format
biff3	.xls	none	single	Excel 3.0 Worksheet Format
biff2	.xls	none	single	Excel 2.0 Worksheet Format
xlml	.xls	none	multi	Excel 2003-2004 (SpreadsheetML)
ods	.ods	ZIP	multi	OpenDocument Spreadsheet
fods	.fods	none	multi	Flat OpenDocument Spreadsheet
wk3	.wk3	none	multi	Lotus Workbook (WK3)
csv	.csv	none	single	Comma Separated Values
txt	.txt	none	single	UTF-16 Unicode Text (TXT)
sylk	.sylk	none	single	Symbolic Link (SYLK)
html	.html	none	single	HTML Document
dif	.dif	none	single	Data Interchange Format (DIF)
dbf	.dbf	none	single	dBASE II + VFP Extensions (DBF)
wk1	.wk1	none	single	Lotus Worksheet (WK1)
rtf	.rtf	none	single	Rich Text Format (RTF)
prn	.prn	none	single	Lotus Formatted Text
eth	.eth	none	single	Ethercalc Record Format (ETH)

• compression only applies to formats with ZIP containers.
• Formats that only support a single sheet require a sheet option specifying the worksheet. If the string is empty, the first worksheet is used.
• writeFile will automatically guess the output file format based on the file extension if bookType is not specified. It will choose the first format in the aforementioned table that matches the extension.

Output Type

The type argument for write mirrors the type argument for read:

type	output
"base64"	string: Base64 encoding of the file
"binary"	string: binary string (byte n is data.charCodeAt(n))
"string"	string: JS string (characters interpreted as UTF8)
"buffer"	nodejs Buffer
"array"	ArrayBuffer, fallback array of 8-bit unsigned int
"file"	string: path of file that will be created (nodejs only)

• For compatibility with Excel, csv output will always include the UTF-8 byte order mark.