chore: simplify redis credential

deploy/saneUrl/index.js

@@ -32,15 +32,7 @@ const redisPort = REDIS_PORT || REDIS_RATE_LIMITING_DB_EPHEMERAL_PORT_6379_TCP_P
  * nb this way to set username and pswd can be risky, but given that site adnimistrator sets the username and pswd via env var
  * it should not be a security concern
  */
-const userPass = (() => {
-  let outstring = ''
-  if (!REDIS_USERNAME && !REDIS_PASSWORD) return outstring
-  if (REDIS_USERNAME) outstring += REDIS_USERNAME
-  if (outstring.length > 0) outstring += ':'
-  if (REDIS_PASSWORD) outstring += REDIS_PASSWORD
-  if (outstring.length > 0) outstring += '@'
-  return outstring
-})()
+const userPass = (REDIS_USERNAME || REDIS_PASSWORD) && `${REDIS_USERNAME || ''}${REDIS_USERNAME ? ':' : ''}${REDIS_PASSWORD || ''}@`
 
 const redisURL = redisAddr && `${redisProto}://${userPass || ''}${redisAddr}:${redisPort}`