const Pako = require('pako'); // get file from command line const file = process.argv[2]; // read file const fs = require('fs'); const data = fs.readFileSync(file); const result = Pako.inflate(data, { to: 'string' }); // write file with suffix .decompressed const path = require('path'); const basename = path.basename(file); const extname = path.extname(file); const filename = basename.slice(0, -extname.length); const newFile = `${filename}.decompressed${extname}`; fs.writeFileSync(newFile, result);