In working with a customer on a new Mail App for OWA, they had a requirement to determine if the mail item being composed is a Reply or Forward or new mail message. Determining is New or Reply/Forward is easy. But getting the Reply/Forward determination is unfortunately… too easy.  Meaning the ONLY way I have been able to determine this is to look at the subject and see if there is a RE: or FW: in there. It’s a little ugly, but this is how it is. And worse – it is language dependent. If you need to support multiple languages you will have to determine the language and then make this function – much larger. So here is the English only version:

[code lang=”javascript” collapse=”true” title=”click to expand if the github.com embedding below is not visible.”]
/// getMailType()
/// This function determines the type of email item currently being composed
/// – If it is a new item, it returns "New"
/// – If it is a reply, it return "Reply"
/// – If it is a Forward it returns "Forward"
/// – And if it cannot determine, it returns "UnknownReplyOrForward"
/// This accepts a function that is called with the resulting value.
function getMailType(returnFunction) {
// get the conversation ID – if it exists
var id = Office.cast.item.toItemCompose(Office.context.mailbox.item).conversationId;
if (id == null) {
// We have a new item
returnFunction("New");
return;
}
else {
// at this point we know we have a reply or forward. Now we determine which on it is.
// we do this by getting the SUBJECT and then – yes – we look and see if it is a
// RE: or FW: or unknown.
Office.cast.item.toItemCompose(Office.context.mailbox.item)
.subject.getAsync(function (result) {
var subject = result.value;
// now this sucks, but the only way to do this is look at the
// beginning of the subject and see it if it RE or FWD and
// even worse, this is language specific…
// and worse yet – if the user changed it, we have no idea
if(subject.toString().toUpperCase.startsWith("RE:")){
returnFunction("Reply");
}
else if(subject.toString().toUpperCase.startsWith("FW:")){
returnFunction("Forward");
}
else {
returnFunction("UnknownReplyOrForward");
}
});
}
}
[/code]

And to test this, I just created a button on my Compose App task pane, that runs the following code:

[code language=”javascript”]
$(‘#getMailType’).click(function () {
getMailType(function (result) {
app.showNotification("This is a: " + result);
});
});
[/code]