What is JS's version of LookVector?

What is JS’s version of LookVector? For example:

X.transform.position = player.skeleton.transform.position.LookVector * 5

theoretically this would move X(an object) 5 studs in front of the players skeleton.

LookVector doesn’t exist in Unity in any language. However, from your description, you’re looking for:

X.transform.position = player.skeleton.transform.position + player.skeleton.transform.forward * 5f;