angles.js
function(p1, p2) {

      var s = this['SCALE'];
      var angle = (TAU + Math.atan2(p2[1] - p1[1], p2[0] - p1[0])) % TAU;

      return angle / TAU * s;
    }
function(p1, p2) {

      var s = this['SCALE'];
      var angle = (TAU + Math.atan2(p2[1] - p1[1], p2[0] - p1[0])) % TAU;

      return angle / TAU * s;
    }
function ( p1 , p2 ) { var s = this [ 'SCALE' ] ; var angle = ( TAU + Math . atan2 ( p2 [ 1 ] - p1 [ 1 ] , p2 [ 0 ] - p1 [ 0 ] ) ) % TAU ; return angle / TAU * s ; }
What is the angle of two points making a line

@param {Array} p1
@param {Array} p2
@returns {number}
What is the angle of two points making a line