Uncaught (in promise) TypeError: n.join is not a function

Question

I have an extension on devops azure, and I 'm newbie in Javascript by the way. I wrote an function to get the name of task after fetch its id from server:

dataService.getDocument("registryKey").then((doc) => {
    let authenToken =  doc.value[doc.count - 1];
    fetch('https://52.221.253.35/api/timelog'+query, {
       method: 'GET',
       headers:{
          'Authentication': authenToken
       }
   }).then((resp) => resp.json()).then(function (data) {
         let index = 1;
         let body = "";
         // foreach the data and i call VSS Http to get work item 's detail
         data.forEach(async function f(item) {
             let result = await witClient.getWorkItems(item.TaskId, ["System.Id", "System.Title"]);
                        body+="<p>"+result['System.Title']+"</p>"
                    $("#table-body").html(body);
                });

but when it runs, it throws an error: Uncaught (in promise) TypeError: n.join is not a function What is wrong here? Thank you for your comment.

Answer 1

Try this:

let result = await witClient.getWorkItems([item.TaskId], ["System.Id", "System.Title"]);
                    body+="<p>"+result['System.Title']+"</p>"
                $("#table-body").html(body);
            });

Note the square brackets around the first parameter.