xlsx-to-js

Xlsx-to-js

A TypeScript-based library for parsing Excel (XLSX) with browser support.

Getting Started

Installation

With npm:

npm install --save xlsx-to-js

Import library:

import { XlsxParser } from "xlsx-to-js";

Usage

Parsing Workbooks

Extract data from spreadsheet bytes

const xlsxParser = new XlsxParser();
const workbook = await xlsxParser.readFile(file, { dense: true, styles: true, drawings: true, skipHiddenRows: true });

The readFile method extract data from spreadsheet bytes stored in a ArrayBuffer.

The second argument to options accepts the properties:

Option	Default	Description
dense	false	When the option dense: false is passed, parsers will skip empty cells.
styles	false	When the opction styles: false is passed, parsers will skip cell styles.
drawings	false	When the option drawings: false is passed, parsers will skip parsing drawings and graphical objects.
skipHiddenRows	false	When the option skipHiddenRows: true is passed, hidden rows will be ignored during parsing.

Render to HTML

Render the parsed workbook as Excel-like HTML.

• Render all sheets at once:

const xlsxParser = new XlsxParser();
const workbook = await xlsxParser.readFile(file, {
  dense: true,
  styles: true,
  drawings: true,
  skipHiddenRows: true,
});

const fullHtml = xlsxParser.toHTML(workbook);
document.getElementById('container')!.innerHTML = fullHtml;

• Render a single sheet (recommended for performance in UIs with tabs):

const xlsxParser = new XlsxParser();
const workbook = await xlsxParser.readFile(file, {
  dense: true,
  styles: true,
  drawings: true,
  skipHiddenRows: true,
});

// Render first sheet (index 0)
const sheetHtml = xlsxParser.toHTMLSheet(workbook, 0);
document.getElementById('sheetView')!.innerHTML = sheetHtml;

Notes:

• Pass styles: true to include cell fonts, colors, alignment, borders, and fills.
• Pass drawings: true to include images, shapes, and textboxes positioned like in Excel.
• The generated HTML includes column letters and row numbers. It also respects merged cells and most layout details.

Supported Features

• Cell Content: strings, numbers, dates (basic serial-date -> locale string), formulas (stored, not evaluated).
• Merged Cells: respects merge ranges and renders proper rowspan/colspan.
• Styles: font family/size, bold/italic, text color, background fill (theme, rgb), horizontal/vertical alignment, wrap, borders (most styles) when styles: true.
• Dimensions: column widths and row heights converted to pixels with Excel-like logic; honors per-column/row overrides and hidden/collapsed.
• Headers: row numbers and column letters like Excel.
• Drawings: images (png/jpg/gif), shapes (fill/border), textboxes (text color, align, font), positioned via anchors when drawings: true.
• Multiple Sheets: render all or one at a time (toHTMLSheet).

Limitations

• No Calc Engine: formulas are not evaluated; cell .formula is exposed, .value is parsed text/number/date.
• Styles Fidelity: border variants, distributed/justify vertical alignment, and some number formats may not fully match Excel.
• Themes/Tint: theme shade/tint handled pragmáticamente; minor color differences possible versus desktop Excel.
• Fonts/MDW: column width conversion depends on runtime font metrics; small pixel drifts may occur across platforms.
• Drawings Coverage: connectors, grouped shapes, rotations, and complex effects are not fully rendered.
• Hidden Rows/Cols: when skipHiddenRows: true, hidden rows are skipped; hidden columns get width 0 but still occupy position.
• Print/Views: print areas, panes freeze, page breaks and advanced view options are not applied to HTML.

Supported Environments

• Browsers: modern Chromium/Firefox/Safari (ES2019+, DOMParser, Canvas for font metrics). Tested on latest Chrome/Edge/Firefox/Safari.
• Node.js: intended for browser use. In Node you must polyfill DOMParser (e.g., jsdom) to use XML parsing and HTML rendering.
• Module Format: published as ESM; works with bundlers like Vite/Webpack/Rollup.

References

• ISO/IEC 29500:2012 "Office Open XML File Formats — Fundamentals And Markup Language Reference"