[keycloak-user] Keycloak Javascript Adapter - Advisable to be used for confidential clients?

I am referring to Keycloak Javascript adapter as mentioned in : https://www.keycloak.org/docs/4.5/securing_apps/index.html#_javascript_ad... I have a confidential client and I have downloaded keycloak-oidc.json containing client secret. Now I am not sure how secure is it to keep this file containing client-secret at the client side. Am I being over concerned?