how to get realtime new transaction data in nodejs from bitcore I want to run a private node, and use it to receive realtime unconfirmed transactions data into my nodejs script.

How do I go about this?
Either you use some nodejs library which would give you a high level wrapper for the bitcoin core api getrawmempool, or make your script hit your local bitcoin instance in the json-rpc format to get the memorypool data your node has.
The memory pool is basically where the transactions stay before getting confirmed in a block. So your script needs to run in regular intervals of time to keep track of the changes too. 

url: http://&lt;username&gt;:&lt;password&gt;@localhost:18332/
post data:{"jsonrpc":1,"id":"curltext", "method":"getrawmempool", "payload":[]}

The username and password is checked from the bitcoin.conf file in the .bitcoin folder. Change the port number to 8332 in case you are running the mainnet daemon.