Cheatsheet

The shortest path from “I want to do X” to working code. Each row names the exact functions you import. The snippets below the index expand the most common patterns. For prose context see Recipes; for every export see API reference.

Each function lives in exactly one subpath — xlsx-kit/io, /node, /streaming, /workbook, /worksheet, /cell, /styles, /chart, /drawing. Function name → subpath is unique, so once you know the name you know where to import from.

Index

Read

Stream-read (huge sheets)

Write

Stream-write (huge sheets)

Cells, formulas, links

Worksheet structure

Drawings

Snippets

Each snippet below corresponds to one row above. Imports are explicit so you can copy-paste a single block into your file.

Read xlsx file (Node) → Workbook

import { loadWorkbook } from 'xlsx-kit/io';
import { fromFile } from 'xlsx-kit/node';

const wb = await loadWorkbook(fromFile('in.xlsx'));

Read xlsx Buffer (Node) → Workbook

import { loadWorkbook } from 'xlsx-kit/io';
import { fromBuffer } from 'xlsx-kit/node';

const wb = await loadWorkbook(fromBuffer(buf));

Read xlsx from fetch (browser) → Workbook

import { fromResponse, loadWorkbook } from 'xlsx-kit/io';

const wb = await loadWorkbook(fromResponse(await fetch('/sheet.xlsx')));

Read xlsx from <input type="file"> (browser) → Workbook

import { fromBlob, loadWorkbook } from 'xlsx-kit/io';

const wb = await loadWorkbook(fromBlob(file));

Iterate every cell of a worksheet → 2D array

import { iterValues } from 'xlsx-kit/worksheet';

const rows = [...iterValues(ws)]; // CellValue[][]

Find the populated extents of a worksheet

import { getMaxRow, getMaxCol } from 'xlsx-kit/worksheet';

const lastRow = getMaxRow(ws);
const lastCol = getMaxCol(ws);

Stream-read: iterate a huge sheet without loading it

import { fromFile } from 'xlsx-kit/node';
import { loadWorkbookStream } from 'xlsx-kit/streaming';

const wb = await loadWorkbookStream(fromFile('big.xlsx'));
const sheet = wb.openWorksheet(wb.sheetNames[0] ?? '');
for await (const row of sheet.iterRows()) {
  console.log(row.map((c) => c.value));
}
await wb.close();

Stream-read: only rows N..M of a huge sheet

import { fromFile } from 'xlsx-kit/node';
import { loadWorkbookStream } from 'xlsx-kit/streaming';

const wb = await loadWorkbookStream(fromFile('big.xlsx'));
const sheet = wb.openWorksheet(wb.sheetNames[0] ?? '');
for await (const row of sheet.iterRows({ minRow: 1_000_000, maxRow: 1_000_100 })) {
  // …
}
await wb.close();

Build a small workbook in memory → Uint8Array

import { workbookToBytes } from 'xlsx-kit/io';
import { addWorksheet, createWorkbook } from 'xlsx-kit/workbook';
import { setCell } from 'xlsx-kit/worksheet';

const wb = createWorkbook();
const ws = addWorksheet(wb, 'Sheet1');
setCell(ws, 1, 1, 'Hello');
const bytes = await workbookToBytes(wb);

Build a small workbook → save to file (Node)

import { saveWorkbook } from 'xlsx-kit/io';
import { toFile } from 'xlsx-kit/node';
import { addWorksheet, createWorkbook } from 'xlsx-kit/workbook';
import { setCell } from 'xlsx-kit/worksheet';

const wb = createWorkbook();
const ws = addWorksheet(wb, 'Sheet1');
setCell(ws, 1, 1, 'Hello');
await saveWorkbook(wb, toFile('out.xlsx'));

Build a small workbook → Buffer (Node)

import { workbookToBuffer } from 'xlsx-kit/node';
import { addWorksheet, createWorkbook } from 'xlsx-kit/workbook';
import { setCell } from 'xlsx-kit/worksheet';

const wb = createWorkbook();
const ws = addWorksheet(wb, 'Sheet1');
setCell(ws, 1, 1, 'Hello');
const buf = await workbookToBuffer(wb); // Buffer

Edit one cell of an existing file (Node)

import { loadWorkbook, saveWorkbook } from 'xlsx-kit/io';
import { fromFile, toFile } from 'xlsx-kit/node';
import { setCell } from 'xlsx-kit/worksheet';

const wb = await loadWorkbook(fromFile('in.xlsx'));
const sheet = wb.sheets[0];
if (sheet?.kind === 'worksheet') {
  setCell(sheet.sheet, 1, 1, 'updated');
}
await saveWorkbook(wb, toFile('out.xlsx'));

Append rows to a worksheet

import { appendRows } from 'xlsx-kit/worksheet';

appendRows(ws, [
  ['name', 'qty'],
  ['apple', 3],
  ['pear', 7],
]);

Stream-write millions of rows to a file

import { toFile } from 'xlsx-kit/node';
import { createWriteOnlyWorkbook } from 'xlsx-kit/streaming';

const wb = await createWriteOnlyWorkbook(toFile('big.xlsx'));
const ws = await wb.addWorksheet('Data');
ws.setColumnWidth(1, 24); // must precede the first appendRow

for (let r = 0; r < 10_000_000; r++) {
  await ws.appendRow([r, `row-${r}`, r * Math.PI]);
}
await ws.close();
await wb.finalize();

Bold + font size + fill on a header cell

import { setBold, setCellBackgroundColor, setFontSize } from 'xlsx-kit/styles';
import { setCell } from 'xlsx-kit/worksheet';

const c = setCell(ws, 1, 1, 'Header');
setBold(wb, c);
setFontSize(wb, c, 14);
setCellBackgroundColor(wb, c, 'FFEFEFEF');

Number format: currency / percent

import { setCellAsCurrency, setCellAsPercent } from 'xlsx-kit/styles';
import { setCell } from 'xlsx-kit/worksheet';

setCellAsCurrency(wb, setCell(ws, 1, 1, 1234.5));
setCellAsPercent(wb, setCell(ws, 1, 2, 0.125));

Number format: date

import { FORMAT_DATE_DATETIME, setCellNumberFormat } from 'xlsx-kit/styles';
import { setCell } from 'xlsx-kit/worksheet';

setCellNumberFormat(wb, setCell(ws, 1, 1, new Date()), FORMAT_DATE_DATETIME);

Add a formula (with cached value)

import { setFormula } from 'xlsx-kit/cell';
import { setCell } from 'xlsx-kit/worksheet';

const c = setCell(ws, 3, 1, null);
setFormula(c, 'SUM(A1:A2)', { cachedValue: 42 });

Make a cell clickable

import { setHyperlink } from 'xlsx-kit/worksheet';

setHyperlink(ws, 'A1', { target: 'https://example.com', display: 'Open' });

Merge cells + freeze the header row

import { makeFreezePane, makeSheetView, mergeCells } from 'xlsx-kit/worksheet';

mergeCells(ws, 'A1:C1');
ws.views.push(makeSheetView({ pane: makeFreezePane('A2') }));

Multiple sheets + a defined name

import { addDefinedName, addWorksheet, createWorkbook } from 'xlsx-kit/workbook';

const wb = createWorkbook();
addWorksheet(wb, 'Q1');
addWorksheet(wb, 'Q2');
addDefinedName(wb, { name: 'Totals', value: 'Q1!$A$1:$A$10,Q2!$A$1:$A$10' });

Promote a range to an Excel Table

import { addExcelTable } from 'xlsx-kit/worksheet';

addExcelTable(wb, ws, {
  name: 'Items',
  ref: 'A1:C4',
  columns: ['SKU', 'Name', 'Price'],
  style: 'TableStyleMedium2',
});

AutoFilter on a header row (no table styling)

import { addAutoFilter } from 'xlsx-kit/worksheet';

addAutoFilter(ws, 'A1:C1');

Dropdown data validation

import { addDataValidation, makeDataValidation } from 'xlsx-kit/worksheet';

addDataValidation(
  ws,
  makeDataValidation({
    type: 'list',
    sqref: 'B2:B100',
    formula1: '"red,green,blue"',
  }),
);

Insert an image at a cell

import { addImageAt, loadImage } from 'xlsx-kit/drawing';

const img = loadImage(bytes); // bytes: Uint8Array
addImageAt(ws, 'B2', img, { widthPx: 200, heightPx: 80 });

Add a clustered column chart

import { makeBarChart, makeBarSeries, makeChartSpace } from 'xlsx-kit/chart';
import { addChartAt } from 'xlsx-kit/drawing';

const chart = makeBarChart({
  barDir: 'col',
  grouping: 'clustered',
  series: [
    makeBarSeries({
      idx: 0,
      tx: { kind: 'literal', value: 'Revenue' },
      cat: { ref: 'Sales!$A$2:$A$4' },
      val: { ref: 'Sales!$B$2:$B$4' },
    }),
  ],
});

const space = makeChartSpace({
  plotArea: { chart },
  title: 'Revenue by region',
  legend: { position: 'r' },
});
addChartAt(ws, 'D2', { space }, { widthPx: 480, heightPx: 320 });