Determines if the mail item is a new mail, reply or forward

getMailType.js

/// 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");
			}
		});
	}
}