How do you select mail messages using JXA script

Question

To select messages in Mac Mail using AppleScript you can use the following syntax:

tell application "Mail"
    set selectedMessages to selected messages of the first message viewer
    set selected messages of the first message viewer to item 1 of selectedMessages
end tell

However a solution for setting the selection using JXA evades me and the Library documentation it not much help either. I have tried:

var app = Application('Mail')
var selectedMessages = app.messageViewer[0].selectedMessages()
app.messageViewer[0].selectedMessages(selectedMessages[0])

and

var app = Application('Mail')
var selectedMessages = app.messageViewer[0].selectedMessages()
app.messageViewer[0].selectedMessages([selectedMessages[0]])

and

var app = Application('Mail')
var selectedMessages = app.messageViewer[0].selectedMessages()
app.messageViewer[0].selectedMessages = selectedMessages

None of these work. Any ideas?

Answer 1

var Mail = Application('Mail');
var msgList = Mail.messageViewers[0];

msgList.selectedMessages = msgList.messages[0]

You'll need to figure our how the messages array is ordered, or use a whose filter.