code: function signedArea(p0, p1, p2) {
      return (p0[0] - p2[0]) * (p1[1] - p2[1]) - (p1[0] - p2[0]) * (p0[1] - p2[1]);
    }
docs: const EPSILON = 1e-9; const abs = Math.abs; TODO https://github.com/w8r/martinez/issues/6#issuecomment-262847164 Precision problem.  module.exports = function equals(p1, p2) { return abs(p1[0] - p2[0]) <= EPSILON && abs(p1[1] - p2[1]) <= EPSILON; }; 
  Signed area of the triangle (p0, p1, p2)
  @param  {Array.<Number>} p0
  @param  {Array.<Number>} p1
  @param  {Array.<Number>} p2
  @return {Number}