sheetjs-clone/docbits/80_parseopts.md

Parsing Options

The exported read and readFile functions accept an options argument:

Option Name	Default	Description
type		Input data encoding (see Input Type below)
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 of type z 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 **
WTF	false	If true, throw errors on unexpected file features **

• 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.
• Currently only XOR encryption is supported. Unsupported error will be thrown for files employing other encryption methods.
• WTF is mainly for development. By default, the parser will suppress read errors on single worksheets, allowing you to read from the worksheets that do parse properly. Setting WTF:1 forces those errors to be thrown.

The defaults are enumerated in bits/84_defaults.js

Input Type

Strings can be interpreted in multiple ways. The type parameter for read tells the library how to parse the data argument:

type	expected input
"base64"	string: base64 encoding of the file
"binary"	string: binary string (n-th byte is data.charCodeAt(n))
"buffer"	nodejs Buffer
"array"	array: array of 8-bit unsigned int (n-th byte is data[n])
"file"	string: filename that will be read and processed (nodejs only)

Guessing File Type

Excel and other spreadsheet tools read the first few bytes and apply other heuristics to determine a file type. This enables file type punning: renaming files with the .xls extension will tell your computer to use Excel to open the file but Excel will know how to handle it. This library applies similar logic:

Byte 0	Raw File Type	Spreadsheet Types
0xD0	CFB Container	BIFF 5/8 or password-protected XLSX/XLSB
0x09	BIFF Stream	BIFF 2/3/4/5
0x3C	XML/HTML	SpreadsheetML / Flat ODS / UOS1 / HTML / plaintext
0x50	ZIP Archive	XLSB or XLSX/M or ODS or UOS2 or plaintext
0x49	Plain Text	SYLK or plaintext
0x54	Plain Text	DIF or plaintext
0xFE	UTF16 Encoded	SpreadsheetML or Flat ODS or UOS1 or plaintext

DBF files are detected based on the first byte as well as the third and fourth bytes (corresponding to month and day of the file date)