Reading files

Use read for data you already have in memory. Use readFile to read a file in Node.

const XLSX = require("@agent-sheet/wasm");

// Make a small file to read.
const src = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(src, XLSX.utils.aoa_to_sheet([["a", "b"], [1, 2], [3, 4]]), "First");
XLSX.utils.book_append_sheet(src, XLSX.utils.aoa_to_sheet([["x"], [9]]), "Second");
XLSX.writeFile(src, "book.xlsx");

const wb = XLSX.readFile("book.xlsx");
console.log(wb.SheetNames);
console.log(wb.Sheets.First["!ref"]);
console.log(wb.Sheets.First.B2);

Output

[ 'First', 'Second' ]
A1:B3
{ t: 'n', v: 2, w: '2' }

The format is detected from the content, not from the file name.

Input types

Set type to tell read how to interpret the data you pass.

type	Input
"string"	text, for formats such as CSV and HTML
"base64"	base64 text
"binary"	a binary string, one character per byte
"buffer"	a Node Buffer
"array"	a Uint8Array, an ArrayBuffer or an array of bytes
"file"	a file path (Node only)

When you leave type out, read guesses from the value you pass.

const XLSX = require("@agent-sheet/wasm");
const fs = require("fs");

const src = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(src, XLSX.utils.aoa_to_sheet([[1]]), "S");
XLSX.writeFile(src, "book.xlsx");

const data = fs.readFileSync("book.xlsx");
console.log(XLSX.read(data).SheetNames);
console.log(XLSX.read(data.toString("base64"), { type: "base64" }).SheetNames);
console.log(XLSX.read(new Uint8Array(data), { type: "array" }).SheetNames);
console.log(XLSX.read(data.toString("binary"), { type: "binary" }).SheetNames);
console.log(XLSX.read("a,b\n1,2", { type: "string" }).SheetNames);

Output

[ 'S' ]
[ 'S' ]
[ 'S' ]
[ 'S' ]
[ 'Sheet1' ]

Read only part of a file

These options save time on large files.

const XLSX = require("@agent-sheet/wasm");

const src = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(src, XLSX.utils.aoa_to_sheet([["a", "b"], [1, 2], [3, 4]]), "First");
XLSX.utils.book_append_sheet(src, XLSX.utils.aoa_to_sheet([["x"], [9]]), "Second");
XLSX.writeFile(src, "book.xlsx");

// Only the sheet names:
const names = XLSX.readFile("book.xlsx", { bookSheets: true });
console.log(names.SheetNames, Object.keys(names));

// Only one sheet, by name or by index:
console.log(Object.keys(XLSX.readFile("book.xlsx", { sheets: "Second" }).Sheets));
console.log(Object.keys(XLSX.readFile("book.xlsx", { sheets: 1 }).Sheets));

// Only the first two rows of each sheet:
console.log(XLSX.readFile("book.xlsx", { sheetRows: 2 }).Sheets.First["!ref"]);

Output

[ 'First', 'Second' ] [ 'SheetNames' ]
[ 'Second' ]
[ 'Second' ]
A1:B2

Dense mode

By default a worksheet is an object with one property per cell (A1, B2, …). With dense: true the cells are in a row array named !data. Dense mode uses less memory for big sheets.

const XLSX = require("@agent-sheet/wasm");

const src = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(src, XLSX.utils.aoa_to_sheet([["a", "b"], [1, 2]]), "First");
XLSX.writeFile(src, "book.xlsx");

const wb = XLSX.readFile("book.xlsx", { dense: true });
const ws = wb.Sheets.First;
console.log(ws["!data"][1][0]);
console.log(ws.A1);

Output

{ t: 'n', v: 1, w: '1' }
undefined

Main read options

See Parsing options for the full list. The ones you use most:

Option	Effect
type	how to interpret the input
cellDates	produce date cells (t: "d") instead of serial numbers
cellStyles	load styles and sheet presentation data
cellNF	keep the number format in z
cellFormula	keep formulas in f (default true)
sheetStubs	create blank cells for cells that only carry formatting
raw	keep delimited-text values as strings
codepage	text encoding of legacy files, see Codepages
WTF	throw on malformed content instead of skipping it

Plain text formats

CSV and other text formats are parsed with the same call. Numbers and dates are detected unless you set raw: true.

const XLSX = require("@agent-sheet/wasm");
const wb = XLSX.read("id,name\n1,Ann\n2,Bob", { type: "string" });
console.log(XLSX.utils.sheet_to_json(wb.Sheets.Sheet1));

const raw = XLSX.read("id\n007", { type: "string", raw: true });
console.log(raw.Sheets.Sheet1.A2.v, typeof raw.Sheets.Sheet1.A2.v);

Output

[ { id: 1, name: 'Ann' }, { id: 2, name: 'Bob' } ]
007 string