The property 'CompanyId' does not exist on type 'SP.Data.ContactsListItem'. Make sure to only use property names that are defined by the type
What causes it and how to fix it:
- A conditional spread hides a phantom column until SharePoint returns 400...(cond ? {…} : {}) bypasses the excess-property check, so a field the list doesn't have reaches the POST and 400s; two scripted sweeps find the restCause and fix →