This dish is very popular. So popular that China, Korea and Japan all have their own versions of this dish. I’ve listed their names below with a brief description in case anyone wants to try making the other variants.
Zha Jiang Mian - Chinese, this is probably the saltiest variant.
Jajangmyeon - Korean, this variant is generally sweeter. It also has a lot more veggies in the sauce so it’s probably healthier (?). The sauce also uses a darker sauce base so the end result is a sauce that is almost black. This is generally how you can distinguish it in photos.
Jajamen - Japanese, this is probably the least popular of the three. It’s much milder compared to the other too versions because it uses much milder ingredients. Instead of very salty bean pastes as a sauce base, the Japanese version uses miso.