How to set lookup properly in javascript

Hi I’m creating a new data row in javascript.

                        {Item__c: row.Id},

The contact__c and contact__r.Name are set properly I can see them in the developer console by displaying I think that’s because the contactModel has the name information.

But Item__c is empty. I do have a model for Item__c. Can you please advise how to set this properly? row.Id has the right value in console.log.

 Using  {field: ‘Item__c’, value: row.Id} worked!