Q: Will my Singapore MacBook Pro work in Indonesia

A Mac works everywhere. Maybe you will need a different power adapter for your Mac, but apart from that, everything will work as it does now

Yes.  You may need a plug adaptor to allow you to plug your charger into the mains supply.

Actually the MBP sold in Indonesia has Singapore's adaptor plug (3 legs instead of 2 round legs like Indonesia's plug) for the cable extension.  As for voltage, I believe that most electronic adaptor supports at least 110v-220v, so that it can be used for charging while travelling out of the country of origin.  You just need to buy plug adaptor (2 round legs) to use in Indonesia.