AddType application/x-javascript .jsgz    
AddType application/octet-stream .datagz

RewriteEngine on 
# If client accepts compressed files 
RewriteCond %{HTTP:Accept-Encoding} gzip 
# and if compressed file exists 
RewriteCond %{REQUEST_FILENAME}gz -f 
# send .ext.gz instead of .ext 
RewriteRule ^(.+)\.(mem|js|data|symbols)$ $1.$2gz

AddEncoding gzip .jsgz 
AddEncoding gzip .datagz
AddEncoding gzip .memgz
AddEncoding gzip .symbolsgz