How not to show a dialog and print a list of strings?

I have something like this:
`$.ajax({
type: 'post',
url: '/test',
data: { 'user' : userIds.join()},
success: function(responsePdfs){
responsePdfs.forEach(function (pdf, index) {
console.log('PDF ', pdf, index);
printJS({printable: pdf, type: 'pdf', base64: true, showModal:false});
});
},
error: function(xhr, exception) {
console.log('Error');
}
});`

My Java post method returns list of strings List. Foreach loop loops twice for 2 PDFs, however the print dialog is opened only once, for the last PDF in a list. It doesn't print the first PDF and for a second it opens a dialog which it shouldn't open. What am I doing wrong here? It's Chrome version 89.0.4389.72.