N/task Module
task.EntityDeduplicationTaskStatus
Object Description: The status of a merge duplicate record task placed into the NetSuite task queue by EntityDeduplicationTask.submit(). Use task.checkStatus(options) with the unique ID for the merge duplicate records task to get this Object. For a complete list of this object’s properties, see EntityDeduplicationTaskStatus Object Members.
Supported Script Types: Server scripts For more information, see SuiteScript 2.0 Script Types.
Module: N/task Module
Since: 2015.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=task.EntityDeduplicationTaskStatus

// Code Example 1

//Add additional code

//...

var dedupeTaskStatus = task.checkStatus({

    taskId: taskId

    });

if (depdupeTaskStatus.status === task.TaskStatus.FAILED)

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_4345799153.html