param 'output' of ExportJob support array of file names
Current param 'output' of ExportJob only support single file name, while render result of multi-input save to file named by sequence suffix.
We suggest param 'output' support an array of file names, each input render result can save to specified file on local disk.
Suggested modify blow:

That is because this module originally only supported a single input and output. I think it was primarily used as a CLI tool at the time.
I added the multiple resource support when I started using the project to run behind an express server.
The exportJob already emits an event with an array of the files.
Here is an example
job.on('job.render.complete', (result) => {
let fileArray = result.results
})
https://github.com/fraserxu/electron-pdf/blob/master/lib/exportJob.js#L158
(Events are used heavily to get additional information during the job. You may want to take some time and explore them to see what is available)
If this addresses your need please close the issue.