How do draw a Line between animated objects

Lets say you have two objects, like Spheres and they are animated in a scene, moving around or bouncing or whatever. The distance between them is changing throughout the scene.

Is it possible to create a Line between the two objects? Essentially so that one end of the line is at the center of one sphere and the other end of the line is at the center of the other sphere? But as the two spheres are moving around, the line is still being maintained between them. The line length would need to be growing/shrinking as the spheres are moving around the scene.

How do you do something like this in Three.js? I’ve looked into Physijs constraints but maybe that is overkill. Would it be more ideal to simply animate the line start/end points on each keyframe to make them match up with the sphere positions?

Maybe I’m overthinking this. I’m not sure.