Send email with attachment using Javascript for Automation

Question

I would like use Javascript for Automation in OS X Yosemite to create a new email message in Mail.app and attach a file to the email. This is my code:

Mail = Application('com.apple.Mail')
message = Mail.OutgoingMessage().make()
message.visible = true
message.toRecipients.push(Mail.Recipient({ address: "[email protected]" }))
message.subject = "Test subject"
message.content = "Lorem ipsum dolor sit"

It works fine until this point. I see a new message window with the recipient, subject, and body text correctly filled in. But I can’t figure out how to add a file attachment to the message. The scripting dictionary for Mail.app indicates that the contents property (an instance of RichText) can contain attachments, but I don’t know how to add one.

I tried this but I get an error:

// This doesn't work.
attachment = Mail.Attachment({ fileName: "/Users/myname/Desktop/test.pdf" })
message.content.attachments = [ attachment ]
// Error: Can't convert types.

I found several examples on the web how to do this in AppleScript, for example this one:

tell application "Mail"
    ...
    set theAttachmentFile to "Macintosh HD:Users:moligaloo:Downloads:attachment.pdf"
    set msg to make new outgoing message with properties {subject: theSubject, content: theContent, visible:true}

    tell msg to make new attachment with properties {file name:theAttachmentFile as alias}
end tell

But I can’t figure out how to convert this to Javascript.

Answer 1

I figured out a way to do this through trial and error, you need to use message.attachments.push(attachment) instead of attachments = [...]

Mail = Application('com.apple.Mail')
message = Mail.OutgoingMessage().make()
message.visible = true
message.toRecipients.push(Mail.Recipient({ address: "[email protected]" }))
message.subject = "Testing JXA"
message.content = "Foo bar baz"

attachment = Mail.Attachment({ fileName: "/Users/myname/Desktop/test.pdf" })
message.attachments.push(attachment)

Answer 2

Building on the answer above by @tlehman, I found that his solution worked very well, except for one thing: The attachments were NOT successful. No errors, no messages, the attachment just was not made to the message. The solution is to use the Path() method.

Here is his solution + the Path() method, which is needed if there are any spaces in the path:

Mail = Application('com.apple.Mail')
message = Mail.OutgoingMessage().make()
message.visible = true
message.toRecipients.push(Mail.Recipient({ address: "[email protected]" }))
message.subject = "Testing JXA"
message.content = "Foo bar baz"

attachment = Mail.Attachment({ fileName: Path("/Users/myname/Desktop/if the file has spaces in it test.pdf") })
message.attachments.push(attachment)