dynamically zip generated pdf files node-archiver

Question

I'm trying to create multiple PDF file using pdfkit, I have an array of users and I create a report for each one, the createTable()Function below returns a Buffer that I send to archiver to zip, once complete the zip file is sent for download to the front end.

My issue is that for some reason, Archiver will sometimes throw a QUEUECLOSED error, if I run the function too many time, sometimes I can run it 10 times and the 11th time I'll get an error and sometimes I get an error after the second time, each time i run it the data is the same and nothing else changed.

Any help is greatly appreciated.

users.forEach(async (worker, index) => {
    createTable(date, worker.associateName, action, worker.email, worker.id, excahngeRate).then(resp => {
        archive.append(resp, { name: worker.associateName + '.pdf' })
        if (index === users.length - 1 === true) {//make sure its the last item in array
            archive.pipe(output)
            archive.finalize();
        }
    }).catch(err => {
        console.log(err)
    })
});

Answer 1

You finalize too soon. The createTable for the last user might not be the last to finish. You should add all to archive and once everything is done, finalize it.

// Use map to get an array of promises
const promises = users.map(async (worker, index) => {
    return createTable(date, worker.associateName, action, worker.email, worker.id, excahngeRate).then(resp => {
        archive.append(resp, { name: worker.associateName + '.pdf' })
    }).catch(err => {
        console.log(err)
    })
});

// Wait for all promises to finish.
Promise.all(promises).then(()=>{
    archive.pipe(output)
    archive.finalize();
});

In your current code, you could console.log just before your IF statement, and log the index of the completed createTable, you'll see they do not finish in order.