Why isn't Node App I wrote using Javascript SDK filtering on extracted fields when searching?

[rajparekh16]

Hello,
I am using JS SDK for Splunk, and have written a Node App. Now when I do a search, I get the results back, but I would like to remove duplicates and would like to use dedup on extracted fields. When I use this it does not work, but the same search string works fine on GUI and returns unique events.
When I use head , it works, but when I use dedup i get no results.
Splunk "version":"6.5.2"

Search String : search index=aaa filter1 filter2 | dedup extractedField1