While flying from the States to Surabaya through Jakarta, I was able to stay the early morning hours of the layover in the GarudaMiles lounge. Pricing sheet is below: one person pays approximately $41 (5/2019). If you have Garuda miles or are part of the Skyteam miles program (https://www.skyteam.com/en/frequent-flyers/) this space can make your trip much more tolerable.
The restroom has showers with great pressure complete with shampoo, shower gel, Q-tips and toiletries. The snack bar had fried treats cookies and many drink choices. Bring your own adapter or borrow one from the front desk. I did not find any USB outlets. Perhaps in the VIP business lounge? Free airport WiFi is a plus.
Atmosphere: The early morning hours in the lounge are busy with maintenance people: cleaning, painting and kitchen work. Still, not as busy or noisy as an airport terminal if you are trying to nap. I turned the TV off as no one seemed to be watching and that improved the atmosphere greatly.
A friend recommended buying a SIM card in Surabaya related to lower cost there. Always travel with an “open” or “unlocked” phone when going international to allow flexibility in choosing data plans. My Verizon International plan on my locked phone is $10/day. No thanks.
Western, Central and Eastern time zones of Indonesia
More services but some only after opening time at 6.