On Centos 7, unix protocol does not aprear to work as udp

[a-boulafia]

Hello,
Sending the same message using unix and upd protocol does not result in the same log message in /var/log/message
eg; :
With the udp protocol:
Sep 5 15:39:36 devcoll01 testNodeJs[2203]: [error] helloWorld
With the unix protocol:
Sep 5 15:44:41 devcoll01 journal: devcoll01 testNodeJZZs[2545]: helloWorld
here are the options i'm using :

unix options:

{protocol:'unix-connect',path:'/dev/log',facility:'local6', app_name:'testNodeJZZs',eol:'\n',type:'BSD'}

udp:

{protocol:'udp', host:'localhost',facility:'local6',app_name:'testNodeJs',localhost:os.hostname() ,type: 'BSD'}

i cannot figure out why it does not work