To provide an easy place to find the behaviors that are included with those data structures.
You definitely need generic node objects to define the nodes.
You could have a completely stateless class/object that would manipulate those nodes and add them and remove them from the data structure.
Well, in principle you could have the node objects be created with an object literal in an outside builder function, and the manipulation also be done by outside functions. That's how it's done in languages without OOP. The question is how far are you willing to go to avoid doing anything that looks like OOP.