VECTOR3 is an open source library for anyone using 3D design with JavaScript. Even if it is small, it can help your code to use fewer characters to calculate a normalized vector, for example. Go deeper and you will definitely find it interesting (be honest :P).
* normalizes vectors
* calculates the dot product
* add/subtract (necessary, right?)
- simplifies in directions (you can doubt as many times as you want :D)