Remember to not get carried away with entities and components. It's totally fine to not have your World as a component. If you know for sure there's only going to be one of something, it doesn't make much sense to make it a component. Components are made to be reused numerous entities, combined with other components.

This doesn't make the game less pure, it makes the system cleaner. Entity systems are just a tool for part of your game, it doesn't need to be all encompassing to be a good system. Use it only where it makes sense to you.

Remember to not get carried away with entities and components. It's totally fine to not have your World as a component. If you know for sure there's only going to be one of something, it doesn't make much sense to make it a component. Components are made to be reused in numerous entities, combined with other components.

This doesn't make the game less pure, it makes the code cleaner. Entity systems are just a tool for part of your game, it doesn't need to be all encompassing to be a good system. Use it only where it makes sense to you.