append hidden content to meeting body in outlook using office js - outlook-addin

Question

using my outlook add-in I need to add some hidden data (some metadata) to meeting body. I tried adding display:none style to html element but no luck. is there any way to achieve this?
below is my code to set body content
function addWorkspaceToItemBody(textToAppend) {
var d = $q.defer();
var item = Office.context.mailbox.item;
item.body.getTypeAsync(
function (result) {
if (result.status == Office.AsyncResultStatus.Failed){
write(result.error.message);
}
else {
// Successfully got the type of item body.
// Set data of the appropriate type in body.
if (result.value == Office.MailboxEnums.BodyType.Html) {
// Body is of HTML type.
// Specify HTML in the coercionType parameter
// of setSelectedDataAsync.
item.body.setSelectedDataAsync(
'<p style="display:none">'+textToAppend+'<\p>',
{ coercionType: Office.CoercionType.Html,
asyncContext: { var3: 1, var4: 2 } },
function (asyncResult) {
if (asyncResult.status ==
Office.AsyncResultStatus.Failed){
d.reject(asyncResult.error.message);
}
else {
d.resolve(asyncResult)
// Successfully set data in item body.
// Do whatever appropriate for your scenario,
// using the arguments var3 and var4 as applicable.
}
});
}
else {
// Body is of text type.
item.body.setSelectedDataAsync(
"",
{ coercionType: Office.CoercionType.Text,
asyncContext: { var3: 1, var4: 2 } },
function (asyncResult) {
if (asyncResult.status ==
Office.AsyncResultStatus.Failed){
d.reject(asyncResult.error.message);
}
else {
d.resolve(asyncResult)
// Successfully set data in item body.
// Do whatever appropriate for your scenario,
// using the arguments var3 and var4 as applicable.
}
});
}
}
});
return d.promise;
}

Answer 1

Below is an example to insert hidden content using the following code. The content is hidden in Outlook 2016, OWA, and Outlook for Android. It may still show up if the content is viewed as plain text in other email clients.
var content =
"<!--[if !mso 9]><!-->"+
'<div class="hidden" style="display:none;max-height:0px;overflow:hidden;">'+
"CONTENT HERE THAT YOU WANT TO HIDE"+
"</div>"+
"<!--<![endif]-->";
Office.context.mailbox.item.body.setSelectedDataAsync("Hello World! " + content, function (asyncResult) {
if (asyncResult.status == "failed") {
console.log("Action failed with error: " + asyncResult.error.message);
}
});
Source