xlsx-writer

name	xlsx-writer
description	Use this skill when the user asks to create, generate, export, or write Excel spreadsheets, XLSX workbooks, CSV-to-XLSX exports, spreadsheet reports, multi-sheet workbooks, summary sheets, data exports, or formatted workbook files. Triggers on phrases like create Excel, create spreadsheet, generate XLSX, export Excel, make workbook, spreadsheet report, save as XLSX, workbook with sheets, data export, and Excel report. Use it to produce usable SheetJS workbooks and tell the user the exact saved path.
emoji	🧩
version	1.1.0
triggers	create excel, create spreadsheet, generate xlsx, generate excel, export xlsx, export excel, make workbook, spreadsheet report, xls, xlsx, workbook, save as XLSX, Excel report, data export

XLSX Writer

Generate Excel spreadsheets using xlsx (SheetJS). Pure Node — works on Windows.

DEPENDENCY CHECK — Run First Time Only

node -e "require('xlsx'); console.log('OK')"

Run from D:\Prometheus. If missing: node workspace\doc-skills-setup.js

---

How It Works

Write a Node script, run it, it outputs a .xlsx file to the workspace. Tell the user where to find it.

---

Simple Single-Sheet Spreadsheet

The fastest path — array of objects → xlsx:

// _tmp_xlsxwrite.js
const XLSX = require('../node_modules/xlsx');

// Your data — array of objects, keys become column headers
const data = [
  { Name: 'Alice Johnson', Role: 'Engineer', Salary: 95000, Department: 'Engineering' },
  { Name: 'Bob Smith',     Role: 'Designer', Salary: 85000, Department: 'Product' },
  { Name: 'Carol White',   Role: 'Manager',  Salary: 110000, Department: 'Operations' }
];

const ws = XLSX.utils.json_to_sheet(data);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, 'Employees');
XLSX.writeFile(wb, 'output.xlsx');
console.log('Created: output.xlsx');

---

Multi-Sheet Workbook

// _tmp_xlsxwrite.js
const XLSX = require('../node_modules/xlsx');

const wb = XLSX.utils.book_new();

// Sheet 1: Revenue
const revenue = [
  { Month: 'Jan', Revenue: 42000, Expenses: 28000, Profit: 14000 },
  { Month: 'Feb', Revenue: 58000, Expenses: 31000, Profit: 27000 },
  { Month: 'Mar', Revenue: 51000, Expenses: 29000, Profit: 22000 }
];
XLSX.utils.book_append_sheet(wb, XLSX.utils.json_to_sheet(revenue), 'Revenue');

// Sheet 2: Customers
const customers = [
  { Company: 'Acme Corp', MRR: 4500, Plan: 'Business', Since: '2023-01' },
  { : ,  : , : ,      :  }
];
..(wb, ..(customers), );

.(wb, );
.();

---

Styled Headers + Column Widths

SheetJS with styling (requires setting cell styles manually):

// _tmp_xlsxwrite.js
const XLSX = require('../node_modules/xlsx');

const headers = ['Product', 'Q1', 'Q2', 'Q3', 'Q4', 'Total'];
const rows = [
  ['Widget A', 1200, 1450, 1380, 1700, null],
  ['Widget B', 800,  950,  1100, 1250, null],
  ['Widget C', 2100, 2300, 2150, 2600, null]
];

// Add formula column for totals (SheetJS supports Excel formula strings)
rows.forEach(row => {
  row[5] = row[1] + row[2] + row[3] + row[4]; // calculated in JS
});

// Build sheet from array-of-arrays (gives more control than json_to_sheet)
const wsData = [headers, ...rows];
const ws = XLSX.utils.aoa_to_sheet(wsData);

// Set column widths
ws['!cols'] = [
  { wch: 16 }, // Product
  { :  }, 
  { :  }, 
  { :  }, 
  { :  }, 
  { :  }  
];


ws[] = { : , : , : , :  };

 wb = ..();
..(wb, ws, );
.(wb, );
.();

---

From Extracted Data (Pipeline Pattern)

When you've already extracted data (from a CSV, JSON, API response) and need to export it:

// _tmp_xlsxwrite.js
const XLSX = require('../node_modules/xlsx');
const fs = require('fs');

// Load previously extracted/processed data
const rawData = JSON.parse(fs.readFileSync('_tmp_data.json', 'utf-8'));

// Normalize to array of objects if needed
const rows = Array.isArray(rawData) ? rawData : rawData.rows || rawData.data || [];

if (rows.length === 0) {
  console.log('No data to write'); process.exit(0);
}

const ws = XLSX.utils.json_to_sheet(rows);
const wb = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(wb, ws, 'Data');
XLSX.writeFile(wb, 'export.xlsx');
console.log(`Created: export.xlsx (${rows.length} rows)`);

---

Summary Sheet Pattern

For reports with a summary sheet + detail sheets:

// _tmp_xlsxwrite.js
const XLSX = require('../node_modules/xlsx');

const wb = XLSX.utils.book_new();

// Summary sheet — key metrics in two-column format
const summary = [
  ['Metric', 'Value'],
  ['Total Revenue', '$284,000'],
  ['Total Customers', 47],
  ['Avg MRR', '$6,042'],
  ['Report Date', new Date().toLocaleDateString()]
];
XLSX.utils.book_append_sheet(wb, XLSX.utils.aoa_to_sheet(summary), 'Summary');

// Detail sheet
const detail = [
  { Customer: 'Acme Corp', MRR: 4500, Status: 'Active' },
  { Customer: 'TechFlow',  MRR: 2200, Status: 'Active' },
  { Customer: 'OldCo',     MRR: 0,    Status: 'Churned' }
];
XLSX..(wb, ..(detail), );

.(wb, );
.();

---

Key SheetJS APIs

Task	Method
Array of objects → sheet	XLSX.utils.json_to_sheet(arrayOfObjects)
Array of arrays → sheet	XLSX.utils.aoa_to_sheet(arrayOfArrays)
Create workbook	XLSX.utils.book_new()
Add sheet to workbook	XLSX.utils.book_append_sheet(wb, ws, 'SheetName')
Write to file	XLSX.writeFile(wb, 'filename.xlsx')
Set column widths	ws['!cols'] = [{ wch: 15 }, ...]
Freeze header row	ws['!freeze'] = { xSplit: 0, ySplit: 1, topLeftCell: 'A2' }
Set row heights	ws['!rows'] = [{ hpt: 20 }, ...]

---

Output Location

Always write to D:\Prometheus\workspace\. Tell the user the exact filename after creation.