How to retrieve term from term store SharePoint online

Question

I have a SharePoint list and I'm retrieving metadata from my list using JavaScript, but I have one issue: how to retrieve metadata of a field that contains terms from the term store?

Here's is my code:

function getmetadata()
{ 
    var listGuid = GetUrlKeyValue("List");
    var itemId = GetUrlKeyValue("ID");
    var clientContext = new SP.ClientContext();
    var item = clientContext.get_web().get_lists().getById(listGuid).getItemById(itemId);
    clientContext.load(item);
    clientContext.executeQueryAsync(
        function(){
             var logos = item.get_item("logo2");
             var code = item.get_item("Code_postal_x002d_batiment");
             var Surface = item.get_item("Surface");
             var complement = item.get_item("Secteur_activite_x002d_complement");
             var porteur = item.get_item("Nom_client");
             var mission = item.get_item("Mission_x002d_Artdesk");
             var vedette = item.get_item("photo_x0020_vedette");
             document.getElementById("logo").innerHTML = logos;
             document.getElementById("codepostal").innerHTML = code;
             document.getElementById("surface").innerHTML = Surface;
             document.getElementById("complement").innerHTML = complement;
             document.getElementById("porteur").innerHTML = porteur;
             document.getElementById("mission").innerHTML = mission;
             document.getElementById("photovedette").innerHTML = vedette;

        },
        function(sender,args){
            alert(args.get_message());
        });
}

For example this is a term from term store: "Mission_x002d_Artdesk", but the value returned is: [object Object]

How can I retrieve the term value from term store?

Answer 1

If the managed metadata field allows multiple values, the object will be of type TaxonomyFieldValueCollection; otherwise it'll be a single TaxonomyFieldValue.

You can grab the Label of single managed metadata field values, but not on collections; you'd need to loop through a collection to grab the Label on each individual value in the collection.

Getting the label of a single-value Taxonomy Field

var fieldValue = item.get_item("FieldName");
var fieldLabel = fieldValue.Label;

Getting the label(s) of a multi-value Taxonomy Field

var fieldValue = item.get_item("FieldName");
var taxEnumerator = fieldValue.getEnumerator();
while(taxEnumerator.moveNext()){
    var currentTerm = taxEnumerator.get_current();
    var label = currentTerm.Label;
    // do something with the label here
}