Angle between two vectors?

[ahvonenj]

Could we get a method for angle between two vectors?`

Something like:

var v1 = new Victor(10, 10);
var v2 = new Victor(20, 20);
var angle = v1.angle(v2);

This would be inherently useful for game programming.

[ahvonenj]

Here is a Gist that I've starred and use currently:

https://gist.github.com/conorbuck/2606166

var p1 = {
    x: 20,
    y: 20
};

var p2 = {
    x: 40,
    y: 40
};

// angle in radians
var angleRadians = Math.atan2(p2.y - p1.y, p2.x - p1.x);

// angle in degrees
var angleDeg = Math.atan2(p2.y - p1.y, p2.x - p1.x) * 180 / Math.PI;