Office.context.mailbox.item.subject.getAsync is not a function

Question

Requirement: Get email subject from outlook inbox by outlook add-in API.

Environment:

1. Outlook add-in (sideload)
2. "Mailbox" MinVersion="1.1"
3. Visual studio code

Code:

async function ReadEmailSubject() {
  document.getElementById("email-subject").innerText = ""; 
  Office.context.mailbox.item.subject.getAsync(function (result) {
    var emailSubjectDiv = document.getElementById("email-subject");
    if (result.status === Office.AsyncResultStatus.Succeeded) {

        var emailSubject = result.value;
        emailSubjectDiv.innerText = emailSubject;
    } else {

        console.error("Failed to get email subject: " + result.error.message);
        emailSubjectDiv.innerText = "Failed to get email body: " + result.error.message;
    }
  });
}

Debug console:

TypeError: Office.context.mailbox.item.subject.getAsync is not a function
    at _callee2$ (e:\office-add-ins\Outlook\yo-main\Outlook Add-in\src\taskpane\taskpane.js:28:39)
    at tryCatch (e:\office-add-ins\Outlook\yo-main\Outlook Add-in\src\taskpane\taskpane.js:2:1)
    at Generator.<anonymous> (e:\office-add-ins\Outlook\yo-main\Outlook Add-in\src\taskpane\taskpane.js:2:1)
    at Generator.next (e:\office-add-ins\Outlook\yo-main\Outlook Add-in\src\taskpane\taskpane.js:2:1)
    at asyncGeneratorStep (e:\office-add-ins\Outlook\yo-main\Outlook Add-in\src\taskpane\taskpane.js:2:1)
    at _next (e:\office-add-ins\Outlook\yo-main\Outlook Add-in\src\taskpane\taskpane.js:2:1)
    at e:\office-add-ins\Outlook\yo-main\Outlook Add-in\src\taskpane\taskpane.js:2:1
    at new Promise (<anonymous>)
    at e:\office-add-ins\Outlook\yo-main\Outlook Add-in\src\taskpane\taskpane.js:2:1
    at _ReadEmailSubject (https://localhost:3000/taskpane.js:266:28) {stack: 'TypeError: Office.context.mailbox.item.subjec…t (https://localhost:3000/taskpane.js:266:28)', message: 'Office.context.mailbox.item.subject.getAsync is not a function'}

What I have tried:

1. change "Mailbox" MinVersion="1.1"
2. use "Office.context.mailbox.item.subject.getAsync({asyncContext: "Getting email subject" },function (result){...})" The error still appeared.

Answer 1

This API is available in compose scenarios only. You will get this error if you try to use this API in read scenarios.