Save PDF files from Flipsnack

app.js

const http = require('http')
const fs = require('fs')

const path = require('path');
const pdf = require('images-to-pdf');


const read = async (i) => new Promise((resolve, reject) => {
    options = {
        host: process.env.HOST,
        port: 80
    }

    let path = process.env.ARG.split('_');

    path[1] = path[1].substring(1, path[1].length);
    path[0] += `_${i}`;

    path = path.join('');

    http.get({...options, path}, function(res){
        var imagedata = ''
        res.setEncoding('binary')
    
        res.on('data', function(chunk){
            imagedata += chunk
        })
    
        res.on('end', async function(){
            await fs.writeFile(`./.tmp/${i}.jpeg`, imagedata, 'binary', function(err){
                if (err) throw err
                console.log('Page %s saved.', i);
                resolve(`./.tmp/${i}.jpeg`);
            })
        })
    })
});

const save = async (indexes) => {
    console.log('Saving to PDF...');
    await pdf(indexes, 'file.pdf');
    console.log('File saved!');
}

const run = async () => {
    var dir = './.tmp';

    if (!fs.existsSync(dir)){
        fs.mkdirSync(dir);
    }
    const indexes = [];

    for(let j = 1; j <= process.env.PAGES; j++){
        let path = await read(j);
        indexes.push(path);
    }

    console.log("Finished downloading");

    await save(indexes);

    if (fs.existsSync('./.tmp')) {
        fs.readdirSync('./.tmp').forEach((file, index) => {
            const curPath = path.join('./.tmp', file);
            if (fs.lstatSync(curPath).isDirectory()) { // recurse
                deleteFolderRecursive(curPath);
            } else { // delete file
                fs.unlinkSync(curPath);
            }
        });
        fs.rmdirSync('./.tmp');
    }
}

run().catch(console.error);

hey how do I use this?

How to use it??