Sheetjs 0 20 3

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