tinyweb-office-cells

Open-source Node.js/TypeScript library for reading, writing, and manipulating Excel XLSX files with full formatting and formula evaluation.

Features

• ✅ Read/Write XLSX files — full round-trip fidelity (preserves unmodified XML)
• ✅ Cell formatting — fonts, colors, borders, fills, number formats, alignment
• ✅ Merge cells — column widths, row heights
• ✅ Formula evaluation — 43 built-in Excel functions
• ✅ Data validation — dropdown lists, numeric ranges, date ranges, custom formulas
• ✅ Conditional formatting — cell value rules, color scales, data bars, formulas
• ✅ Named ranges — workbook and sheet-scoped defined names
• ✅ Hyperlinks — external URLs, internal sheet references, email links
• ✅ Comments — cell comments with author and size support
• ✅ AutoFilter — column filters with custom, color, dynamic, and top-10 filters
• ✅ Page breaks — horizontal and vertical page break management
• ✅ Sheet/workbook protection — password-based protection with granular permissions
• ✅ Document properties — title, author, subject, keywords, and custom properties
• ✅ Page setup — orientation, paper size, margins, print area, headers/footers
• ✅ Freeze panes — freeze rows and columns
• ✅ Dual API naming — both camelCase and snake_case method names
• ✅ Sheet rendering — export worksheets to HTML or PNG screenshots (via Puppeteer)
• ✅ TypeScript-first — full type declarations included
• ✅ Zero native dependencies — pure JavaScript, works everywhere Node.js runs

Installation

npm install tinyweb-office-cells

Quick Start

Create a Workbook and Save

import { Workbook, SaveFormat } from 'tinyweb-office-cells';

// Create a new workbook
const workbook = new Workbook();
const sheet = workbook.worksheets.get(0);

// Set cell values
sheet.cells.get('A1').putValue('Name');
sheet.cells.get('B1').putValue('Score');
sheet.cells.get('A2').putValue('Alice');
sheet.cells.get('B2').putValue(95);
sheet.cells.get('A3').putValue('Bob');
sheet.cells.get('B3').putValue(87);

// Add a formula
sheet.cells.get('B4').setFormula('=SUM(B2:B3)');

// Save to file
await workbook.save('output.xlsx');

Read an Existing File

import { Workbook } from 'tinyweb-office-cells';

const workbook = new Workbook();
await workbook.loadFile('input.xlsx');

const sheet = workbook.worksheets.get(0);
console.log(sheet.cells.get('A1').value); // Read cell value
console.log(sheet.name);                  // Sheet name

Apply Formatting

import { Workbook } from 'tinyweb-office-cells';

const workbook = new Workbook();
const sheet = workbook.worksheets.get(0);
const cell = sheet.cells.get('A1');
cell.putValue('Hello, Excel!');

// Get cell style and modify
const style = cell.getStyle();
style.font.name = 'Arial';
style.font.size = 14;
style.font.bold = true;
style.font.color = '#FF0000';
style.fill.patternType = 'solid';
style.fill.fgColor = '#FFFF00';
style.borders.top.lineStyle = 'thin';
style.borders.top.color = '#000000';
style.alignment.horizontal = 'center';
cell.setStyle(style);

await workbook.save('formatted.xlsx');

API Reference

Workbook

The main entry point for creating and manipulating Excel files.

const workbook = new Workbook();

// Load from file
await workbook.loadFile('path/to/file.xlsx');

// Load from buffer
await workbook.loadBuffer(buffer);

// Save to file
await workbook.save('output.xlsx');
await workbook.save('output.xlsx', SaveFormat.XLSX);

// Save to buffer
const buffer = await workbook.saveToBuffer(SaveFormat.XLSX);

// Access worksheets
workbook.worksheets;           // WorksheetCollection
workbook.worksheets.get(0);    // By index
workbook.worksheets.get('Sheet1'); // By name
workbook.worksheets.add('NewSheet');

// Workbook protection
workbook.properties.protection.lockStructure = true;
workbook.properties.protection.password = 'secret';

// Document properties
workbook.documentProperties.title = 'My Report';
workbook.documentProperties.author = 'John Doe';
workbook.documentProperties.subject = 'Q4 Sales';

Worksheet

Represents a single sheet in the workbook.

const sheet = workbook.worksheets.get(0);

// Properties
sheet.name = 'DataSheet';
sheet.isVisible = true;
sheet.tabColor = '#FF0000';

// Cells
sheet.cells.get('A1').putValue('Hello');

// Merge cells
sheet.cells.merge(0, 0, 2, 3); // startRow, startCol, rowCount, colCount

// Column width and row height
sheet.cells.setColumnWidth(0, 20);  // Column A = 20
sheet.cells.setRowHeight(0, 30);    // Row 1 = 30

// Freeze panes
sheet.freezePanes(1, 0);  // Freeze first row

// Page setup
sheet.pageSetup.orientation = 'landscape';
sheet.pageSetup.paperSize = 'A4';

// Sheet protection
sheet.protect('password');
sheet.protection.sheet = true;
sheet.protection.formatCells = false;

Cell / Cells

Access and manipulate individual cells.

const cells = sheet.cells;

// Get a cell (creates if not exists)
const cell = cells.get('A1');
// Also supports: cells.get(0, 0)

// Set values
cell.putValue('text');      // String
cell.putValue(42);          // Number
cell.putValue(true);        // Boolean
cell.putValue(new Date());  // Date

// Read values
cell.value;          // Raw value
cell.stringValue;    // String representation
cell.type;           // CellDataType

// Formulas
cell.setFormula('=SUM(A1:A10)');
cell.formula;        // Get formula string
cell.hasFormula();   // Check if cell has formula

// Styling
const style = cell.getStyle();
style.font.bold = true;
cell.setStyle(style);

// Comments
cell.comment = { text: 'Note', author: 'Admin' };

Style (Font, Fill, Borders, Alignment, NumberFormat)

Full cell formatting support.

const style = cell.getStyle();

// Font
style.font.name = 'Calibri';
style.font.size = 12;
style.font.bold = true;
style.font.italic = true;
style.font.underline = 'single';
style.font.strikethrough = true;
style.font.color = '#0000FF';

// Fill
style.fill.patternType = 'solid';
style.fill.fgColor = '#FFFF00';
style.fill.bgColor = '#FFFFFF';

// Borders
style.borders.top.lineStyle = 'thin';      // thin, medium, thick, dashed, dotted, double
style.borders.top.color = '#000000';
style.borders.bottom.lineStyle = 'double';
style.borders.left.lineStyle = 'medium';
style.borders.right.lineStyle = 'thin';
style.borders.diagonal.lineStyle = 'thin';

// Alignment
style.alignment.horizontal = 'center';   // left, center, right, fill, justify
style.alignment.vertical = 'center';     // top, center, bottom
style.alignment.wrapText = true;
style.alignment.textRotation = 45;
style.alignment.indent = 2;
style.alignment.shrinkToFit = true;

// Number format
style.numberFormat.formatCode = '#,##0.00';
style.numberFormat.formatCode = '0.00%';
style.numberFormat.formatCode = 'yyyy-mm-dd';
style.numberFormat.formatCode = '$#,##0.00';

// Protection
style.protection.locked = true;
style.protection.hidden = true;

cell.setStyle(style);

FormulaEvaluator

Evaluate formulas in cells.

import { FormulaEvaluator } from 'tinyweb-office-cells';

// Set up formulas
sheet.cells.get('A1').putValue(10);
sheet.cells.get('A2').putValue(20);
sheet.cells.get('A3').setFormula('=SUM(A1:A2)');

// Evaluate all formulas
const evaluator = new FormulaEvaluator(workbook);
evaluator.evaluateAll();

console.log(sheet.cells.get('A3').value); // 30

Data Validation

Add data validation rules to cells.

import { DataValidation, DataValidationType, DataValidationOperator } from 'tinyweb-office-cells';

const validations = sheet.dataValidations;

// Dropdown list
const dv = validations.add();
dv.sqref = 'A1:A10';
dv.type = DataValidationType.LIST;
dv.formula1 = '"Apple,Banana,Cherry"';

// Numeric range
const numDv = validations.add();
numDv.sqref = 'B1:B10';
numDv.type = DataValidationType.WHOLE;
numDv.operator = DataValidationOperator.BETWEEN;
numDv.formula1 = '1';
numDv.formula2 = '100';
numDv.showErrorMessage = true;
numDv.errorTitle = 'Invalid Input';
numDv.error = 'Please enter a number between 1 and 100';

Conditional Formatting

Apply conditional formatting rules.

const cfCollection = sheet.conditionalFormattings;

// Cell value rule
const cf = cfCollection.add();
cf.sqref = 'A1:A20';
cf.type = 'cellIs';
cf.operator = 'greaterThan';
cf.formula1 = '90';
cf.priority = 1;
cf.dxf = {
  font: { color: '#006100' },
  fill: { bgColor: '#C6EFCE' },
};

Hyperlinks

Add hyperlinks to cells.

const hyperlinks = sheet.hyperlinks;

// External URL
hyperlinks.add('A1', 1, 1, 'https://example.com');
const link = hyperlinks.get(0);
link.textToDisplay = 'Visit Example';
link.screenTip = 'Click to open';

// Internal reference
hyperlinks.add('A2', 1, 1, '#Sheet2!A1');

Named Ranges

Define and use named ranges.

// Add a defined name
workbook.definedNames.add('SalesData', 'Sheet1!$A$1:$D$100');
workbook.definedNames.add('TaxRate', '0.08');

// Use in formulas
sheet.cells.get('E1').setFormula('=SUM(SalesData)');

AutoFilter

Apply auto-filtering to data ranges.

const autoFilter = sheet.autoFilter;
autoFilter.range = 'A1:D100';

// Add a filter column
const fc = autoFilter.addFilterColumn(0);
fc.setValues(['Active', 'Pending']);

Comments

Add comments to cells.

const cell = sheet.cells.get('A1');
cell.comment = {
  text: 'This is a comment',
  author: 'Admin',
  width: 200,
  height: 100,
};

Page Setup

Configure print settings.

sheet.pageSetup.orientation = 'landscape';
sheet.pageSetup.paperSize = 'A4';
sheet.pageSetup.printArea = 'A1:H50';
sheet.pageSetup.fitToPagesTall = 1;
sheet.pageSetup.fitToPagesWide = 1;

Formula Support

The built-in formula evaluator supports 43 Excel functions across 7 categories:

Math & Statistics (16 functions)

SUM · AVERAGE · MIN · MAX · COUNT · COUNTA · ABS · ROUND · ROUNDUP · ROUNDDOWN · INT · MOD · POWER · SQRT · CEILING · FLOOR

String Functions (11 functions)

CONCATENATE · CONCAT · TEXT · LEN · TRIM · UPPER · LOWER · LEFT · RIGHT · MID · SUBSTITUTE · REPT

Logic Functions (4 functions)

IF · AND · OR · NOT

Lookup & Reference (4 functions)

VLOOKUP · HLOOKUP · INDEX · MATCH

Date & Time (6 functions)

TODAY · NOW · DATE · YEAR · MONTH · DAY

Information Functions (5 functions)

ISNUMBER · ISTEXT · ISBLANK · ISERROR · ISNA

Other Functions (2 functions)

VALUE · CHOOSE

Also Supports

• Arithmetic operators: + - * / ^
• Comparison operators: = <> < > <= >=
• String concatenation: &
• Cell references: A1, $A$1, Sheet1!A1
• Range references: A1:B5
• Defined names / named ranges
• Nested formulas with recursive evaluation
• Error values: #VALUE!, #REF!, #NAME?, #DIV/0!, #N/A

Examples

Create and Save a Workbook

import { Workbook } from 'tinyweb-office-cells';

const wb = new Workbook();
const ws = wb.worksheets.get(0);
ws.name = 'Sales Report';

// Headers
['Product', 'Q1', 'Q2', 'Q3', 'Q4', 'Total'].forEach((h, i) => {
  const cell = ws.cells.get(0, i);
  cell.putValue(h);
  const style = cell.getStyle();
  style.font.bold = true;
  style.fill.patternType = 'solid';
  style.fill.fgColor = '#4472C4';
  style.font.color = '#FFFFFF';
  cell.setStyle(style);
});

// Data
const data = [
  ['Widget A', 1200, 1350, 1100, 1500],
  ['Widget B', 800, 920, 870, 1050],
];

data.forEach((row, r) => {
  row.forEach((val, c) => {
    ws.cells.get(r + 1, c).putValue(val);
  });
  // Total formula
  ws.cells.get(r + 1, 5).setFormula(`=SUM(B${r + 2}:E${r + 2})`);
});

await wb.save('sales-report.xlsx');

Read and Modify an Existing File

import { Workbook } from 'tinyweb-office-cells';

const wb = new Workbook();
await wb.loadFile('existing.xlsx');

const ws = wb.worksheets.get(0);

// Read all data
for (let r = 0; r < 100; r++) {
  for (let c = 0; c < 10; c++) {
    const cell = ws.cells.get(r, c);
    if (cell.value !== null) {
      console.log(`${cell.name}: ${cell.value}`);
    }
  }
}

// Modify a cell
ws.cells.get('A1').putValue('Updated!');
await wb.save('modified.xlsx');

Data Validation with Dropdown

import { Workbook, DataValidationType } from 'tinyweb-office-cells';

const wb = new Workbook();
const ws = wb.worksheets.get(0);

ws.cells.get('A1').putValue('Select a fruit:');

const dv = ws.dataValidations.add();
dv.sqref = 'B1';
dv.type = DataValidationType.LIST;
dv.formula1 = '"Apple,Banana,Cherry,Date,Elderberry"';
dv.showDropDown = true;
dv.showInputMessage = true;
dv.inputTitle = 'Fruit Selection';
dv.inputMessage = 'Choose a fruit from the list';

await wb.save('dropdown.xlsx');

Conditional Formatting

import { Workbook } from 'tinyweb-office-cells';

const wb = new Workbook();
const ws = wb.worksheets.get(0);

// Add some scores
for (let i = 0; i < 20; i++) {
  ws.cells.get(i, 0).putValue(Math.floor(Math.random() * 100));
}

// Highlight scores above 80 in green
const cf = ws.conditionalFormattings.add();
cf.sqref = 'A1:A20';
cf.type = 'cellIs';
cf.operator = 'greaterThanOrEqual';
cf.formula1 = '80';
cf.dxf = {
  fill: { bgColor: '#C6EFCE' },
  font: { color: '#006100' },
};

await wb.save('conditional.xlsx');

Render Worksheet to HTML / PNG

Convert any worksheet to an HTML table with full styling, or capture a PNG screenshot.

import { Workbook, worksheetToHtml, worksheetToPng } from 'tinyweb-office-cells';

const wb = new Workbook();
await wb.loadFile('report.xlsx');
const ws = wb.worksheets.get(0);

// Render to HTML string (with inline styles for fonts, fills, borders, merges)
const html = worksheetToHtml(ws);
// Or as a full HTML page:
const fullHtml = worksheetToHtml(ws, { fullPage: true });

// Render only a specific range:
const rangeHtml = worksheetToHtml(ws, { range: 'A1:D10' });
const rangePng = await worksheetToPng(ws, { range: 'B2:F20' });

// Render to PNG (requires puppeteer as peer dependency)
// npm install puppeteer
const pngBuffer = await worksheetToPng(ws);
fs.writeFileSync('sheet.png', pngBuffer);

// Also available as convenience methods on Worksheet:
const html2 = ws.toHtml();
const png2 = await ws.toPng();

Render options:

Option	Type	Default	Description
fullPage	boolean	false	Wrap table in a full HTML document
defaultFont	string	'Calibri,Arial,sans-serif'	Default font family
range	string	—	Render only cells within this A1 range, e.g. 'A1:D10'
viewportWidth	number	1200	Viewport width for PNG rendering

Note: PNG rendering requires puppeteer as an optional peer dependency. Install it separately: npm install puppeteer

API Compatibility

This library provides dual naming conventions for maximum compatibility:

camelCase (TypeScript)	snake_case (Python-compat)
cell.putValue(v)	cell.put_value(v)
cell.getStyle()	cell.get_style()
cell.setStyle(s)	cell.set_style(s)
cell.hasFormula()	cell.has_formula()
cell.setFormula(f)	cell.set_formula(f)
cell.stringValue	cell.string_value
cells.setColumnWidth()	cells.set_column_width()
cells.setRowHeight()	cells.set_row_height()
workbook.loadFile()	workbook.load_file()
workbook.saveToBuffer()	workbook.save_to_buffer()

Both naming styles work identically — use whichever fits your codebase.

TypeScript

Full TypeScript declarations are included. All classes, interfaces, enums, and types are exported:

import {
  Workbook,
  Worksheet,
  Cell,
  Cells,
  Style,
  Font,
  Fill,
  Border,
  Borders,
  Alignment,
  NumberFormat,
  Protection,
  SaveFormat,
  FormulaEvaluator,
  DataValidation,
  DataValidationCollection,
  DataValidationType,
  DataValidationOperator,
  ConditionalFormat,
  ConditionalFormatCollection,
  Hyperlink,
  HyperlinkCollection,
  AutoFilter,
  FilterColumn,
  DefinedName,
  DefinedNameCollection,
  HorizontalPageBreakCollection,
  VerticalPageBreakCollection,
  SheetProtection,
  PageSetup,
  FreezePane,
  WorkbookProtection,
  DocumentProperties,
  // Rendering
  worksheetToHtml,
  worksheetToPng,
} from 'tinyweb-office-cells';

Dependencies

Package	Purpose
jszip	XLSX ZIP container read/write
fast-xml-parser	XML parsing and generation
puppeteer (optional)	PNG screenshot rendering (only needed for worksheetToPng)

No native/binary dependencies — works on any platform where Node.js runs.

License

MIT