How to iterate through each item in list based on Title

I need to filter based on Title, then check whether the same row value exists in any other row in the sharepoint list, if present throw an error else update an item to the list

Hello @Madhumitha_Umanath,

Welcome to Plumsail Community!

You can check if the value exists in SharePoint list using PnPjs function. See the example in this post: