xlsx-extract-js

super-simple async XLSX reader with low memory footprint (forked to use sax rather than node-expat for better windows compat)

Usage no npm install needed!

<script type="module">
  import xlsxExtractJs from 'https://cdn.skypack.dev/xlsx-extract-js';
</script>

README

xlsx-extract

-- extracts data from XLSX files with low memory footprint

xlsx-files can get pretty large, so nodejs & full featured xlsx-modules often reach memory limits or just use more than is needed for that task.

(--max-old-space-size & --stack_size can't help you all the time either)

hence these magnificent features:

  • filestreams are piped & xml is parsed with sax parser node-expat
  • get rows/cells each by callback or write them to a .tsv or .json file
  • empty lines at the end of the file are ignored

Convenience API


    var XLSX = require('xlsx-extract').XLSX;

    //dump by row
    new XLSX().extract('path/to/file.xlsx', {sheet_nr:1})
        .on('row', function (row) {
            console.log(row);  //row is a array of values or []
        })
        .on('cell', function (cell) {
            console.log(cell); //cell is a value or null
        })
        .on('error', function (err) {
            console.error(err);
        })
        .on('end', function (err) {
            console.log('eof');
        });

    //dump by row in tsv-format
    new XLSX().extract('path/to/file.xlsx', {sheet_nr:1, format:'tsv'})
        .on('row', function (row) {
            console.log(row); //row is a tsv line
        })
        .on('cell', function (cell) {
            console.log(cell); //cell is a tsv value
        })
        .on('error', function (err) {
            console.error(err);
        })
        .on('end', function (err) {
            console.log('eof');
        });

    //convert to tsv-file
    new XLSX().convert('path/to/file.xlsx', 'path/to/destfile.tsv')
        .on('error', function (err) {
            console.error(err);
        })
        .on('end', function () {
            console.log('written');
        })

    //convert to json-file
    new XLSX().convert('path/to/file.xlsx', 'path/to/destfile.json')
        .on('error', function (err) {
            console.error(err);
        })
        .on('end', function () {
            console.log('written');
        })


    demo_options = {
        sheet_nr: 1, // default 1 - the number of the sheet starting on 1
        ignore_header: 0,  // default 0 - the number of header lines to ignore
        include_empty_rows: false,  // default false - include empty rows in the middle/at start
        date1904: false,    // default false - use date 1904 conversion
        tsv_float_comma: false  // default false - use "," als decimal point for floats
        format: '',     // default array - convert to 'array'||'json'||'tsv'||'obj'
        raw_values: false,   // default false - do not apply cell formats (get values as string as in xlsx)
        convert_values: { // apply cell number formats or not
            ints: true,  // rounds to int if number format is for int
            floats: true,  // rounds floats according to float number format
            dates: true,   // converts xlsx date to js date
            bools: true   // converts xlsx bool to js boolean
        }
     };


TODO

  • better error handling
  • more testing
  • publish to npm
  • docu for command-line tool xlsxe
  • docu for XLSX.utils
  • docu for formats callback