get lookup additional fields as part of rest call

{WebUrl}/_api/web/lists/GetByTitle('SPR_RequestItems')/Items?$select=SPR_RequestItem_SAP_MaterialCode/SPR_SAP_MaterialCode,SPR_RequestItem_SAP_MaterialCode/SPR_SAP_MaterialDescription&$filter=SPR_RequestNumber%20eq%20144&$expand=SPR_RequestItem_SAP_MaterialCode&$top=5000

Add multiple items in sharepoint list using JSOM

var itemArray = [];
   for (var i = 1; i <= totalSPRIRowsCount; i++)
   {
       
           var listspRequests = context.get_web().get_lists().getByTitle(listspRequestsTitle);
           var newItemInfo = new SP.ListItemCreationInformation();
           newItemInfo.set_folderUrl(_spPageContextInfo.webAbsoluteUrl + "/Lists/SPR_RequestItems/" + curdate.getFullYear() + "/" + monthNames[curdate.getMonth()]);
           var spRequestItem = listspRequests.addItem(newItemInfo);
           UpdateSPRequestItem(spRequestItem,i);
           itemArray.push(spRequestItem);
           context.load(itemArray[itemArray.length-1]);
   }
   context.executeQueryAsync(
                       function(sender,args)
                       {
                           //waitDialogSubmit.close(SP.UI.DialogResult.OK);
                           SendMailOnSubmit();
                       },
                       function (sender, arg)
                       {
                           alert("error in update request : " + arg.get_message());
                           //waitdialogsubmit.close(sp.ui.dialogresult.ok);
                           redirectoncompletion();
                       });

Defered object usage in sharepoint

function getCachedSearches() {
    var dfd = $.Deferred(function () {
        var list = context
                .get_web()
                .get_lists()
                .getByTitle('MyList');

        cached_searches = list.getItems('');

        context.load(cached_searches);

        context.executeQueryAsync(
           function () {
               dfd.resolve();
           },
           function (sender, args) {
               dfd.reject(args.get_message());
           }
        );
    });
    return dfd.promise();
}

function addCachedSearch(phrase) {
    var dfd = $.Deferred(function () {
        var list = context
                .get_web()
                .get_lists()
                .getByTitle('CachedSearches');

        var create_item = new SP.ListItemCreationInformation();
        var list_item = list.addItem(create_item);

        list_item.set_item('Title', phrase);

        list_item.update();

        context.load(list_item);

        context.executeQueryAsync(
           function () {
               dfd.resolve();
           },
           function (sender, args) {
               dfd.reject(args.get_message());
           }
        );
    });
    return dfd.promise();
}

function doSearch() {
    addCachedSearch($('#phrase').val())
        .then(getCachedSearches);
}