docs.sheetjs.com/docz/docs/02-getting-started/01-installation/03-nodejs.md

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NodeJS	getting-started/index	getting-started/examples/index	3	summary Server-side and other frameworks using NodeJS modules

import current from '/version.js'; import Tabs from '@theme/Tabs'; import TabItem from '@theme/TabItem'; import CodeBlock from '@theme/CodeBlock';

Package tarballs are available on https://cdn.sheetjs.com.

{"https://cdn.sheetjs.com/xlsx-" + current + "/xlsx-" + current + ".tgz"} is the URL for version {current}

Installation

Tarballs can be directly installed using a package manager:

{`\ npm rm --save xlsx npm i --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`} {`\ pnpm rm xlsx pnpm install --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`} {`\ yarn remove xlsx yarn add https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`}

:::caution pass

Newer releases of Yarn may throw an error:

Usage Error: It seems you are trying to add a package using a https:... url; we now require package names to be explicitly specified.
Try running the command again with the package name prefixed: yarn add my-package@https:...

The workaround is to prepend the URL with xlsx@:

{\ yarn add xlsx@https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz}

:::

:::tip pass

Watch the repo or subscribe to the RSS feed to be notified when new versions are released!

:::

:::caution Snyk Bugs

Snyk security tooling may report errors involving "Prototype Pollution":

Prototype Pollution [Medium Severity][https://security.snyk.io/vuln/SNYK-JS-XLSX-5457926]

As noted in the Snyk report:

The issue is resolved in version 0.19.3

Snyk is falsely reporting vulnerabilities. It is a bug in the Snyk tooling.

Until Snyk fixes the bugs, the official recommendation is to suppress the warning.

:::

Legacy Endpoints

:::danger pass

Older releases are technically available on the public npm registry as xlsx, but the registry is out of date. The latest version on that registry is 0.18.5

This is a known registry bug

The SheetJS CDN https://cdn.sheetjs.com/ is the authoritative source for SheetJS modules.

For existing projects, the easiest approach is to uninstall and reinstall:

{`\ npm rm --save xlsx npm i --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`} {`\ pnpm rm xlsx pnpm install --save https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`} {`\ yarn remove xlsx yarn add https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz`}

When the xlsx library is a dependency of a dependency, the overrides field in package.json can control module resolution:

{\ { // highlight-start "overrides": { "xlsx": "https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz" } // highlight-end }}

:::

Vendoring

For general stability, making a local copy of SheetJS modules ("vendoring") is strongly recommended. Vendoring decouples projects from SheetJS infrastructure.

0. Remove any existing dependency on a project named xlsx:

{`\ npm rm --save xlsx`} {`\ pnpm rm xlsx`} {`\ yarn remove xlsx`}

1. Download the tarball (xlsx-{current}.tgz) for the desired version. The current version is available at {"https://cdn.sheetjs.com/xlsx-" + current + "/xlsx-" + current + ".tgz"}

{\ curl -o https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz}

2. Create a vendor subfolder at the root of your project:

mkdir -p vendor

3. Move the tarball from step (1) to the vendor folder:

{\ mv xlsx-${current}.tgz vendor}

4. If the project is managed with a version control system, add the tarball to the source repository. The Git VCS supports the add subcommand:

{\ git add vendor/xlsx-${current}.tgz}

5. Install the tarball using a package manager:

{`\ npm i --save file:vendor/xlsx-${current}.tgz`} {`\ pnpm install --save file:vendor/xlsx-${current}.tgz`} {`\ yarn add file:vendor/xlsx-${current}.tgz`}

:::caution pass

Newer releases of Yarn may throw an error:

{\ Usage Error: The file:vendor/xlsx-${current}.tgz string didn't match the required format (package-name@range). Did you perhaps forget to explicitly reference the package name?}

The workaround is to prepend the URI with xlsx@:

{\ yarn add xlsx@file:vendor/xlsx-${current}.tgz}

:::

The package will be installed and accessible as xlsx.

Usage

The package supports CommonJS require and ESM import module systems.

:::info pass

It is strongly recommended to use CommonJS in NodeJS.

:::

CommonJS require

By default, the module supports require and it will automatically add support for encodings, streams and file system access:

var XLSX = require("xlsx");

ESM import

The package also ships with xlsx.mjs, a script compatible with the ECMAScript module system. When using the ESM build in NodeJS, some dependencies must be loaded manually.

:::danger ECMAScript Module Limitations

The original ECMAScript module specification only supported top-level imports:

import { Readable } from 'stream';

If a module is unavailable, there is no way for scripts to gracefully fail or ignore the error. This presents an insurmountable challenge for libraries.

To contrast, the SheetJS CommonJS modules gracefully handle missing dependencies since require failures are errors that the library can catch and handle.

---

Patches to the specification added two different solutions to the problem:

• "dynamic imports" will throw errors that can be handled by libraries. Dynamic imports will taint APIs that do not use Promise-based methods.

/* Readable will be undefined if stream cannot be imported */
const Readable = await (async() => {
  try {
    return (await import("stream"))?.Readable;
  } catch(e) { /* silently ignore error */ }
})();

• "import maps" control module resolution, allowing library users to manually shunt unsupported modules.

These patches were released after browsers adopted ESM! A number of browsers and other platforms support top-level imports but do not support the patches.

---

For the ESM build, there were four unpalatable options:

A) Generate a module script for browsers, a module script for ViteJS, a module script for Deno, and a module script for NodeJS and BunJS.

B) Remove all optional features, including support for non-English legacy files.

C) Add all optional features, effectively making the features mandatory.

D) Introduce special methods for optional dependency injection.

The SheetJS team chose option (D). NodeJS native modules are still automatically loaded in the CommonJS build, but NodeJS ESM scripts must now load and pass the dependencies to the library using special methods.

---

It is strongly recommended to use CommonJS in NodeJS scripts!

:::

Filesystem Operations

The set_fs method accepts a fs instance for reading and writing files using readFile and writeFile:

import * as XLSX from 'xlsx';

/* load 'fs' for readFile and writeFile support */
import * as fs from 'fs';
XLSX.set_fs(fs);

Stream Operations

The set_readable method accepts a stream.Readable instance for use in stream methods including XLSX.stream.to_csv:

import * as XLSX from 'xlsx';

/* load 'stream' for stream support */
import { Readable } from 'stream';
XLSX.stream.set_readable(Readable);

Encoding Support

The set_cptable method accepts an instance of the SheetJS codepage library for use in legacy file format processing. The cpexcel.full.mjs script must be manually loaded. xlsx/dist/cpexcel.full.mjs can be imported:

import * as XLSX from 'xlsx';

/* load the codepage support library for extended support with older formats  */
import * as cpexcel from 'xlsx/dist/cpexcel.full.mjs';
XLSX.set_cptable(cpexcel);

NextJS

:::danger pass

fs cannot be imported from the top level in NextJS pages. This will not work:

/* it is safe to import the library from the top level */
import { readFile, utils, set_fs } from 'xlsx';
/* it is not safe to import 'fs' from the top level ! */
// highlight-next-line
import * as fs from 'fs'; // this import will fail
set_fs(fs);

This is a design flaw in NextJS!

:::

For server-side file processing, fs should be loaded with a dynamic import within a lifecycle function:

/* it is safe to import the library from the top level */
import { readFile, utils, set_fs } from 'xlsx';
import { join } from 'path';
import { cwd } from 'process';

export async function getServerSideProps() {
// highlight-next-line
  set_fs(await import("fs")); // dynamically import 'fs' in `getServerSideProps`
  const wb = readFile(join(cwd(), "public", "sheetjs.xlsx"));
  // ...
}

The NextJS demo includes complete examples.