Help with getting the value of a look up field

Question

Currently, I am using an ajax request to access the list items. The fields that are not lookups come as expected but the lookup fields come across as an ID of the object that corresponds to its original list. How can I get the title of the lookup? I have been looking at a lot of post but I cannot figure out how to adapt the things I have found to my code.

My code posted below is just the request and the saving of the data. My ajax code looks like:

 jQuery.ajax({

        url: siteUrl + "/_api/lists/getbytitle('" + listName + "')/items", 
        type: "GET",
        headers: {
            "accept": "application/json;odata=verbose",
        },
        success: function (data) {
            jQuery.each(data.d.results, function (index, item) {
                listItem =  item;
                  //creates the new object
                var taskHolder = new Task(
                    item.ID,
                    item.Title,
                    item.Name,
                    item.Client,
                    item.Assigned_x0020_To,
                    item.Status
                );    

Answer 1

You need to use the $expand option in your query string.

siteUrl + "/_api/lists/getbytitle('" + listName + "')/items?$select=NameOfLookup/FieldYouWant&$expand=NameOfLookup/NameOfFieldYouWant"

So yours would be:

"/_api/lists/getbytitle('" + listName + "')/items?$select=$expand=status_x0028_test_x0029/Title&$expand=status_x0028_test_x0029/Title

This will bring back all of the associated data. Here I have a list called Test List and a lookup field called Status. The 2013 REST API does not support bulk loading the data like the ListData.svc REST service did/does.

Bulk expansion and selection of related items is not supported. --MSDN

So you have to specify the field you want in both the select and expand. Here is example output from my list in O365.

{
    "d": {
        "results": [
            {
                "__metadata": {
                    "id": "26f2b95d-ae86-44b7-bc69-dda79c88d742",
                    "uri": "https://domain.com/_api/Web/Lists(guid'efd16a43-aaf4-44fd-a9a1-4634afe328ac')/Items(2)",
                    "etag": "\"1\"",
                    "type": "SP.Data.Test_x0020_ListListItem"
                },
                "Status": {
                    "__metadata": {
                        "id": "86127a54-7c19-49c6-8e48-e4f56919433e",
                        "type": "SP.Data.StatusesListItem"
                    },
                    "Title": "Development"
                },
                "Title": "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dol",
                "StatusId": 3
            }
        ]
    }
}

Notice the JSON contain the Status field shown in the image witht he value of the Title field in the source list which is "Development"

"Status": {
    "__metadata": {
        "id": "86127a54-7c19-49c6-8e48-e4f56919433e",
        "type": "SP.Data.StatusesListItem"
    },
    "Title": "Development"
}

Answer 2

What is the solution to the get the value of lookup field

var table = $('#example').DataTable({ "filter": true, "bDestroy": true, "bProcessing": true, "aaData": data.d.results, "aoColumns": [ { "mData": "ID" }, { "mData": "Title" },{ "mData": "lookupfield" },]