This idea belongs to skyklown on discord but we were discussing how na Event condition that is triggered on value changed would be neat.
It would be good for both code cleanliness and optimization for games that have a lot of number managing.
A way to dispatch a signal for events to be ran when a specific variable has been affected. This could be useful for example in a scenario where you have 10 different events that can cause "Subtract Damage from HP" or "Add Heal to HP" events.
In the current case what you would do is to create a function, to and make sure to call that function each time in the code that variable has been affected. For example:
This can get a bit messy when more modular groups of events can affect the same variable. You make a note to remember that when you're making a change to HP variable, send this function. When you make a change to Kills variable, you send this function.
The alternative is to watch that variable on every tick and apply that to things like UI sometimes. Which is good for clean code but bad for optimization.