var updatedProducts= search.create({

                

type: search.Type.ITEM,

                

filters: [

                    

['custitem_f3mg_magento_stores', <http://search.Operator.IS|search.Operator.IS>, '2'],

                    

'and',

                    

[

                        

[

                        

['type', search.Operator.ANYOF, 'InvtPart'],

                        

'and',

                        

['lastquantityavailablechange', search.Operator.ONORAFTER, '04/01/2020 12:00 am']

                        

],

                        

'or',

                        

[

                            

['type', search.Operator.ANYOF, 'Kit'],

                            

'and',

                            

['lastquantityavailablechange','memberitem',search.Operator.ONORAFTER, '04/01/2020 12:00 am']

                        

],

                        

'or',

                        

[

                            

['type', search.Operator.ANYOF, ["InvtPart","Kit"]],

                            

'and',

                            

['lastquantityavailablechange', search.Operator.ONORAFTER, '04/01/2020 12:00 am']

                        

]

                    

]

                

]

            

});

ERROR:

{"type":"error.SuiteScriptError","name":"SSS_INVALID_SRCH_OPERATOR","message":"An nlobjSearchFilter contains an invalid operator, or is not in proper syntax: memberitem.","stack":["createError(N/error)","execute()","createError(N/error)"],"cause":{"name":"SSS_INVALID_SRCH_OPERATOR","message":"An nlobjSearchFilter contains an invalid operator, or is not in proper syntax: memberitem."},"id":"","notifyOff":false,"userFacing":true}

Trying to create a saved search with conditional expression but following error encountered.

create the search in the ui first

create saved search in UI and use this extension

It worked .. Thanks @D17339 @battk