Adding a makeOrthogonal method

[ttmarek]

I've got a need for finding an orthogonal (perpendicular) vector of a certain magnitude in one of my projects.

I have a function that does the job, but I'd prefer to make it a part of Victor.js. Here's the function:

  /**
   * Returns a new vector thats orthogonal/perpendicular to the given
   * vector.
   * Mathematical rules:
   * - the dot product of two orthogonal vectors is zero.
   * - the magnitude of a 2d vector is the square root of the sum of
   *   its components.
   * - ^ two equations. components = the two unknowns.
   */
  getOrthogonal(vector, magnitude) {
    magnitude = magnitude || 1
    if (vector.x === 0) {
      return new Victor(magnitude, 0)
    }
    if (vector.y === 0) {
      return new Victor(0, magnitude)
    }
    const j = Math.sqrt((Math.pow(magnitude, 2) /
                         (1 + (Math.pow(vector.y, 2) /
                               Math.pow(vector.x, 2)))))
    const i = -(vector.y / vector.x) * j
    return new Victor(i, j)
  }

I was wondering if you would accept a merge request for a method that would work as follows:

var vec1 = new Victor(100, 200);
var vec2 = vec1.makeOrthogonal(10);
// vec 2 is a vector with a magnitude of 10 that's orthogonal to vec1