Can't add item to list in SharePoint Online app

Question

This is an extension of my previous question... it was resolved but a new issue has come up after getting past that.

Here's the code I'm currently using:

var clientContext = new SP.ClientContext("http://sitecollection/sites/Dev");
var oList = clientContext.get_web().get_lists().getByTitle('User List');
var item = new SP.ListItemCreationInformation();
var oListItem = oList.addItem(item);

oListItem.set_item('Last Name', 'toby');
oListItem.update();

clientContext.load(oListItem);

clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));

This fails on the callback (I think). See the below screenshot:

I am unsure where I am going wrong here... on my previous question, someome had mentioned using app context, something like this:

var context = new SP.ClientContext.get_current();
var hostContext = new SP.AppContextSite(context, hostUrl);
var hostWeb = hostContext.get_web();

But I can't call load on hostWeb... can anyone help me out here?

Answer 1

This error occurs due to the undeclared callback functions in SP.ClientContext.executeQueryAsync method:

SP.ClientContext.executeQueryAsync(succeededCallback, failedCallback)

The method accepts parameters:

• succeededCallback - A function or a delegate of the method to call if the request executes successfully
• failedCallback - A function or a delegate of the method to call if the request fails to execute

Solution

Add the missing callback functions, for example:

function onQuerySucceeded(sender, args) {
    //List Item has been created successfully...
}

function onQueryFailed(sender, args) {
    //Process error goes here...
}

References

How to: Complete basic operations using JavaScript library code in SharePoint 2013