Where do I start with simple JavaScript state management?

Fenster

I have a pair of elements that need to be toggled based on:

• Window size.
• Window scroll position.
• On click.

Scroll
It's a navigational menu and its toggle button. At bigger sizes, the menu appears. When I scroll down, the menu is hidden and the button appears, and vice versa.

Click
When the menu button is clicked, the menu appears until the window is scroll or resized, and their conditions are evaluated again.

Resize
When the window is below a certain size, the scroll action is disabled, and the menu is permanently hidden unless the menu button is clicked.

Thing is, I have all three actions running separately, but I just cannot conceive of a way to link all three together, that is: to tie each action to a central variable which tracks state and propagates a change when a condition is met. I turn up a complete blank, and I don't know what's the best solution.

Where do I start with this sort of problem?

Giblet

You want something like observables. Lot's of libraries support this, look at Knockout or something similar.

Fenster

Will give it a try, thank you sir!