SheetJS
3fde651a8c
- added to TS definition and tests - clarified behavior of plaintext files (fixes #641 h/t @dskrvk) - removed old test files
6.1 KiB
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 |
| cellText | true | Generated formatted text to the .w field |
| cellDates | false | Store dates as type d (default is n) |
| dateNF | If specified, use the string for date code 14 ** | |
| 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
cellNFis false, formatted text will be generated and saved to.w - In some cases, sheets may be parsed even if
bookSheetsis false. bookSheetsandbookPropscombine to give both sets of informationDepswill be an empty object ifbookDepsis falsybookFilesbehavior depends on file type:keysarray (paths in the ZIP) for ZIP-based formatsfileshash (mapping paths to objects representing the files) for ZIPcfbobject for formats using CFB containers
sheetRows-1rows will be generated when looking at the JSON object output (since the header row is counted as a row when parsing the data)bookVBAmerely 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:1forces 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
Implementation Details (click to show)
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 or WQ3/QPW |
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 |
0x00 |
Record Stream | Lotus WK* or Quattro Pro 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)
Plaintext format guessing follows the priority order:
| Format | Test |
|---|---|
| HTML | starts with <html |
| XML | starts with < |
| DSV | starts with /sep=.$/, separator is the specified character |
| TSV | one of the first 1024 characters is a tab char "\t" |
| CSV | one of the first 1024 characters is a comma char "," |
| PRN | (default) |
Why are random text files valid? (click to show)
Excel is extremely aggressive in reading files. Adding an XLS extension to any display text file (where the only characters are ANSI display chars) tricks Excel into thinking that the file is potentially a CSV or TSV file, even if it is only one column! This library attempts to replicate that behavior.
The best approach is to validate the desired worksheet and ensure it has the expected number of rows or columns. Extracting the range is extremely simple:
var range = XLSX.utils.decode_range(worksheet['!ref']);
var ncols = range.e.c - range.r.c + 1, nrows = range.e.r - range.s.r + 1;