compress-epub is an npm package designed to compress .epub files up to 91% of their original size by compressing the images included in the epubs. It allows specifying a compression level from 1 to 10.
You can install the package via npm:
npm install compress-epubconst compressEpub = require('compress-epub');
import compressEpub from 'compress-epub';// Return a buffer with the new epub compressed
const buffer = await compressEpub('stephenking.epub');
// Save the new file in the indicated path
await compressEpub('stephenking.epub', {output: './newfile.epub'});
// Example with all options
await compressEpub('stephenking.epub', {
quality: 10, /* 1 to 10 */
output: './newfile.epub',
outputDir: '/tmp/out', // where epub are decompressed
debug: false,
});You can try it in this page: https://compressepub.com/