Get session id in tomcat access logs for angular js application

We are trying to print session id in access logs using '%S' in server.xml. The application is developed using angular js.

However it prints "-" instead of session id.

server.xml

<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="sessionId=%S host=%h %l %u %t &quot;%r&quot; %s %b" />

Access Logs:

sessionId=- host=127.0.0.1 - - [12/May/2017:13:44:32 +0100] "GET /application/img/sort-icn-down.png HTTP/1.1" 200 1114

Does angular js application create session id automatically?