One of the most used in industry approaches to pathfinding in things like RTSes is what's called a flow field. It's a bit like a precalculated pathfinding map.
These are some of the most interesting for what you can accomplish (pathfinding a ton of units at once!).
These are some of the most interesting for what you can accomplish (pathfinding a ton of units at once!).
A great resource for that is this blog:
https://howtorts.github.io/
It has working javascript examples and other related topics like flocking behavior.