How do I add all contents of 2 different google drive folders in GmailApp

Question

I am trying to add all contents of 2 different folders in google drive to my GmailApp so that email contains all the files from both folders.

Sample Code: it throws an error Exception:

Invalid argument: attachment at sendEmail(Code:180:20)

         var contents = DriveApp.getFolderById('***').getFiles();

         var contentspdf = DriveApp.getFolderById('***').getFiles();
        
            var attach = [];

            while(contents.hasNext()){

                 var file = contents.next();

                 if (file.getMimeType() == "application/pdf"){

                     attach.push(file);

               }
          }
        
          var attachtwo = [];

          while(contentspdf.hasNext()){

              var files = contentspdf.next();

              if (files.getMimeType() == "application/pdf"){

                 attachtwo.push(files);
             
               }
         }

         GmailApp.sendEmail(currentEmail, Subject, messageBody,{
         
               attachments: [attach, attachtwo,],

               name: 'Test'
         });

Answer 1

You can use Spread syntax (...) to put all the attachments into the attachments argument:

attachments: [...attach, ...attachtwo]

---

Solution:

 var contents = DriveApp.getFolderById('***').getFiles();

 var contentspdf = DriveApp.getFolderById('***').getFiles();

    var attach = [];

    while(contents.hasNext()){

         var file = contents.next();

         if (file.getMimeType() == "application/pdf"){

             attach.push(file);

       }
  }

  var attachtwo = [];

  while(contentspdf.hasNext()){

      var files = contentspdf.next();

      if (files.getMimeType() == "application/pdf"){

         attachtwo.push(files);
     
       }
 }

 GmailApp.sendEmail(currentEmail, Subject, messageBody,{
 
       attachments: [...attach, ...attachtwo],

       name: 'Test'
 });

---

Please make sure the V8 Runtime environment is enabled.