sheetjs-0-20-3

name	sheetjs-0-20-3
description	Spreadsheet data toolkit for reading, writing, and converting 40+ file formats including XLSX, CSV, JSON, HTML, ODS. Use when working with spreadsheet files, converting between data formats, exporting tabular data to Excel, or importing legacy workbook formats in browser or Node.js environments.

SheetJS 0.20.3

Overview

SheetJS Community Edition is a JavaScript spreadsheet data toolkit for reading, writing, and converting spreadsheet files across 40+ file formats. It runs in browsers, Node.js, Deno, Bun, and other JavaScript environments. The library provides a unified in-memory data model (Common Spreadsheet Format) that abstracts away format-specific details, enabling seamless data conversion between spreadsheet formats, JSON, CSV, HTML tables, and arrays.

Key capabilities:

• Read XLSX, XLSB, XLS, ODS, CSV, JSON, HTML, Numbers, DBF, Lotus 1-2-3, Quattro Pro, and more
• Write XLSX, XLSB, XLML, CSV, TSV, HTML, RTF, SYLK, DIF, DBF, ODS, FODS
• Convert between any supported format via the unified CSF data model
• Extract data as JSON objects, arrays of arrays, CSV strings, or HTML tables
• Export HTML TABLE elements to XLSX files
• All processing is local — no data sent to third parties, no telemetry

When to Use

• Converting between spreadsheet formats (e.g., XLS to XLSX, ODS to CSV)
• Exporting tabular data from APIs or databases to Excel files
• Importing legacy .xls or .numbers files in a web application
• Reading HTML TABLE elements and converting to spreadsheet files
• Processing CSV/TSV data with spreadsheet format support
• Batch processing multiple workbook sheets across formats
• Building spreadsheet-aware features in Node.js, Deno, Bun, or browser apps

Core Concepts

The Common Spreadsheet Format (CSF)

SheetJS uses a plain JavaScript object model — no classes or prototypes. This makes it compatible with Web Workers' structured clone algorithm. Every structure is a simple object with keys and values.

A workbook (wb) contains:

• wb.SheetNames — ordered list of sheet names
• wb.Sheets — object mapping sheet names to worksheet objects
• wb.Props / wb.Custprops — file properties
• wb.Workbook — workbook-level attributes (defined names, views, VBA)

A worksheet (ws) is a plain object where:

• Keys not starting with ! are A1-style addresses mapping to cell objects
• ws["!ref"] — the used range (e.g., "A1:C10")
• ws["!data"] — dense mode array storage (when dense: true option used)

A cell object has:

• t — type: b (boolean), e (error), n (number), d (date), s (string), z (stub)
• v — underlying value
• z — number format string
• w — formatted text
• f — formula as A1-style string

Library Access

// Browser (standalone script)
// XLSX is available as a global variable

// Node.js (CommonJS)
var XLSX = require("xlsx");

// Frameworks / Bundlers (ESM)
import * as XLSX from "xlsx";

Core Workflow: Read → Transform → Write

// 1. Read/parse a file
var wb = XLSX.read(data, {type: "array"});  // or type: "binary", "base64", "string", "buffer"

// 2. Access data
var sheetName = wb.SheetNames[0];
var ws = wb.Sheets[sheetName];

// 3. Extract data in desired format
var jsonData = XLSX.utils.sheet_to_json(ws);
var csvData = XLSX.utils.sheet_to_csv(ws);
var htmlData = XLSX.utils.sheet_to_html(ws);

// 4. Write/export
XLSX.writeFile(wb, "output.xlsx");

Creating a Workbook from Scratch

// From Array of Arrays
var ws = XLSX.utils.aoa_to_sheet([
  ["Name", "Age"],
  ["Alice", 30],
  ["Bob", 25]
]);
var wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "People");
XLSX.writeFile(wb, "people.xlsx");

// From Array of Objects
var ws = XLSX.utils.json_to_sheet([
  { Name: "Alice", Age: 30 },
  { Name: "Bob", Age: 25 }
]);
var wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "People");
XLSX.writeFile(wb, "people.xlsx");

Exporting HTML TABLE to XLSX

// Create workbook from existing HTML table element
var wb = XLSX.utils.table_to_book(document.getElementById("myTable"));
XLSX.writeFile(wb, "export.xlsx");

Installation

Node.js (npm/pnpm/yarn)

npm i --save https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz

Browser (Standalone Script)

<script src="https://cdn.sheetjs.com/xlsx-0.20.3/package/dist/xlsx.full.min.js"></script>

Deno

import * as XLSX from "https://esm.sh/sheetjs@0.20.3/stable/xlsx/xlsx.mjs";

Bun

// Bun supports Node.js CommonJS modules directly
const XLSX = require("xlsx");

Usage Examples

Export JSON API Data to XLSX

const response = await fetch("https://api.example.com/users");
const users = await response.json();

const ws = XLSX.utils.json_to_sheet(users);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, "Users");
XLSX.writeFile(wb, "users.xlsx");

Read Legacy XLS File and Export to CSV

const fileBuffer = await fs.promises.readFile("legacy.xls");
const wb = XLSX.read(fileBuffer, {type: "buffer"});

wb.SheetNames.forEach(name => {
  const ws = wb.Sheets[name];
  const csv = XLSX.utils.sheet_to_csv(ws);
  console.log(`Sheet "${name}":`, csv);
});

Convert HTML Table to Spreadsheet

// Read from DOM table
const wb = XLSX.utils.table_to_book(document.getElementById("dataTable"), {raw: true});
XLSX.writeFile(wb, "table-export.xlsx");

Dense Mode for Large Worksheets

const wb = XLSX.read(data, {type: "array", dense: true});
const ws = wb.Sheets[wb.SheetNames[0]];

// Access cell at row 5, column 2 (0-indexed)
const cell = ws["!data"][5]?.[2];

Advanced Topics

Data Model (CSF): Deep dive into cell, sheet, and workbook objects — Data Model API Reference: Complete function documentation for read, write, and streaming — API Reference Utilities: sheet_to_json, sheet_to_csv, aoa_to_sheet, json_to_sheet, table_to_book and more — Utilities File Formats: Supported formats, range limits, constellation libraries — File Formats