Convert Excel (XLS/XLSX) to PDF in Node.js — Step‑by‑step guide

Prerequisites

Verify your Node.js and npm versions:

node -v
npm -v

Install LibreOffice (only for the first approach)

Prefer a GUI installer? Download it from the LibreOffice website(opens in a new tab).

After installation, verify that the soffice binary is on the PATH:

libreoffice --version

Approach 1 — Using libreoffice-convert

Why choose libreoffice-convert

• Free and open source (MPL 2.0).
• Supports a broad range of Office file types out of the box.
• Great for batch jobs or migrations when LibreOffice is already installed.

Installation

mkdir excel-to-pdf && cd excel-to-pdf
npm init -y
npm i libreoffice-convert

This command creates a new directory named excel-to-pdf, initializes a new Node.js project, and installs the libreoffice-convert package.

Converting Excel documents to PDF using libreoffice-convert

1. Create a new file named index.mjs, and import the required modules:

import path from "node:path";
import { readFile, writeFile } from "node:fs/promises";
import libre from "libreoffice-convert";
import { promisify } from "node:util";

libre.convertAsync = promisify(libre.convert);

In the code above, you imported the necessary modules: path for working with file paths, fs.promises for file system operations, and libreoffice-convert, along with its asynchronous conversion method.

2. Define the file paths and read the input file:

async function convertExcelWithLibre() {
  const inputPath = path.resolve("example.xlsx");
  const outputPath = path.resolve("example.pdf");

  // Read the input file.
  const xlsxBuf = await readFile(inputPath);
}

Here, you defined the output extension as 'pdf' and set the input and output paths. Then, you used fs.readFile to asynchronously read the input Excel document.

3. Convert to PDF format:

async function convertExcelWithLibre() {
  // ....

  // Convert to PDF format with an undefined filter.
  let pdfBuf = await libre.convertAsync(xlsxBuf, ext, undefined);
}

Here, you used the libre.convertAsync method to convert the Excel document’s contents (in xlsxBuf) to PDF format. The third argument is the filter, which is left undefined. LibreOffice automatically selects a suitable filter based on the input and output formats.

4. Save the converted PDF:

async function convertExcelWithLibre() {
  // ...

  // Save the converted PDF.
  await writeFile(outputPath, pdfBuf);
  console.log("Conversion finished:", outputPath);
}

convertExcelWithLibre();

You saved the converted PDF data (in pdfBuf) to the specified output path using fs.writeFile.

Here’s the complete code:

import path from "node:path";
import { readFile, writeFile } from "node:fs/promises";
import libre from "libreoffice-convert";
import { promisify } from "node:util";

libre.convertAsync = promisify(libre.convert);

async function convertExcelWithLibre() {
  try {
    const inputPath = path.resolve("document.xlsx");
    const outputPath = path.resolve("example.pdf");

    const xlsxBuf = await readFile(inputPath);
    const pdfBuf = await libre.convertAsync(xlsxBuf, "pdf", undefined);

    await writeFile(outputPath, pdfBuf);
    console.log("Conversion finished:", outputPath);
  } catch (err) {
    console.error("Conversion failed:", err);
  }
}

convertExcelWithLibre();

Run it with:

node index.mjs

Approach 2 — Using Nutrient Node.js SDK

Unlike libreoffice-convert, Nutrient Node.js SDK doesn’t rely on third-party software like LibreOffice to convert documents. It relies on its own technology built from the ground up.

Why choose Nutrient Node.js SDK

Features of Nutrient Node.js SDK

Nutrient Node.js SDK offers a range of features that make it a powerful choice for document conversion within Node.js applications:

• Versatile conversion — Convert PDF, Word, Excel, PowerPoint, TIFF, JPG, and PNG files seamlessly, without relying on third-party tools or MS Office licenses.

• Custom font support — Preserve document integrity by handling custom fonts intelligently during conversion, ensuring consistent visual representation.

• Diverse file support — Handle a wide array of formats, including DOCX, XLSX, and PPTX, as well as image types like PNG and JPEG.

• Advanced rendering — Render PDF pages into PNG or WebP formats for versatile visualization options.

Integrating Nutrient Node.js SDK

1. Initialize a new Node.js project:

npm init -y

This command creates a package.json file in your project directory, which is essential for managing your project’s dependencies.

2. Install the Nutrient Node.js SDK package:

npm install @nutrient-sdk/node

3. Place your Office document (e.g. example.xlsx) in your project directory.

4. Create a new JavaScript file named index.mjs in your project directory. This script will handle the conversion process:

import { load } from "@nutrient-sdk/node";
import { readFileSync, writeFileSync } from "node:fs";

async function convertExcelWithNutrient() {
  const excel = readFileSync("document.xlsx");

  const instance = await load({
    document: excel,
  });

  const pdf = await instance.exportPDF({});

  writeFileSync("converted.pdf", Buffer.from(pdf));
  await instance.close();
  console.log("Done! File written to converted.pdf");
}

convertExcelWithNutrient().catch(console.error);

In this script, the load() function from the @nutrient-sdk/node package is used to load the Office document and initiate the conversion process. The converted PDF is then saved as converted.pdf in your project directory.

By default, the resulting PDF will include a Nutrient watermark. To exclude the watermark, you can specify the license property with a key and appName when calling the load() function. For details on obtaining a trial license key, contact Sales.

5. Execute the script in your terminal to initiate the conversion process:

node index.mjs

Once executed, the script will convert the Office document to PDF and save the resulting PDF as converted.pdf in your project directory.

Conclusion

In this post, you explored two approaches to document conversion in Node.js applications. The first part covered using the libreoffice-convert library for seamless Excel-to-PDF conversion.

In the second part, you learned about Nutrient Node.js SDK, a robust SDK offering versatile document conversion features. Whether you prefer libreoffice-convert’s simplicity or Nutrient’s power, you can now integrate efficient document conversion into your Node.js projects. Choose the solution that fits your needs, and enhance your document management and conversion capabilities.

To get started with Nutrient Node.js SDK, you can either:

• Start your free trial to test the library and see how it works in your application.
• Launch our demo to see the viewer in action.

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