Converting DOCX to WEBP with Node.js

This guide shows how to convert a DOCX image to WEBP in Node.js with the Sharp package. This requires PDF as an intermediary step, if you would like to know more read the main article.

Installing Prerequisites#

These instructions are written for Ubuntu 24.04; it should be relatively simple to adapt them for operating system distributions to suit your own needs.

1. update the apt package manager:

apt update

2. LibreOffice, to convert DOCX to PDF:

apt install -y libreoffice

3. libpoppler so Sharp can convert PDFs to images:

apt install -y libpoppler-glib-dev

4. build tools:

apt install -y build-essential pkg-config meson ninja-build cmake libglib2.0-dev libexpat1-dev

5. libraries you need for parity with a standard distribution of Sharp:

apt install -y libjpeg-turbo8-dev libpng-dev libwebp-dev libtiff-dev libgif-dev libcgif-dev libimagequant-dev libheif-dev libdav1d-dev liblcms2-dev libexif-dev zlib1g-dev libbrotli-dev

Building libvips#

libvips is a library written in C, which Sharp uses to convert images. If you want to convert file types which are not supported out-of-the-box, you will have to rebuild libvips:

curl -L -O https://github.com/libvips/libvips/releases/download/v8.18.0/vips-8.18.0.tar.xz
tar xf vips-8.18.0.tar.xz
cd vips-8.18.0
meson setup build --prefix=/usr/local
ninja -C build
ninja -C build install
ldconfig
cd ..

If you would like to know more, you can read about it here.

Installing Node Packages#

LibreOffice accessible from Node.js without an intermediary, install it:

npm i libreoffice

You will have to install these and build Sharp with your local libvips:

npm i node-addon-api
npm explore sharp -- npm run build

Code#

Create a file (e.g. example.js) with the following contents:

import sharp from "sharp";
import * as path from 'path';
import {readFileSync} from 'fs';
import libre from 'libreoffice';
import {promisify} from "util";
libre.convertAsync = promisify(libre.convert);

const pdfBuffer = await libre.convertAsync(readFileSync('test.docx'), '.pdf', undefined);
sharp(pdfBuffer).webp().toFile('from_docx.webp');

Run with:

node example.js