old_contents: var Fabric = require('fabric').fabric || fabric;
  var mixin = require('./mixin');
  
  var Arrow = Fabric.util.createClass(require('./shape_line').klass, {
     type: 'arrow',
     shapeName: 'arrow',
  
     _stroke: function(ctx) {
        var angle = this._getAngle();
        var rad = this._getLength();
        var canvasSize = this._canvasSize();
  
        var size = Math.min(canvasSize / 20, (rad / 10) + canvasSize / 80);
        var headWidthRadians = Math.PI / 6;
        var x  = Math.cos(angle - headWidthRadians) * size;
        var y  = Math.sin(angle - headWidthRadians) * size;
        var x2 = Math.cos(angle + headWidthRadians) * size;
        var y2 = Math.sin(angle + headWidthRadians) * size;
        ctx.translate(-this._getDeltaX()/2, -this._getDeltaY()/2);
        ctx.moveTo(x, y);
        ctx.lineTo(0, 0);
        ctx.lineTo(x2, y2);
  
        this.callSuper('_stroke', ctx);
     }
  });
  
  module.exports.klass = Arrow;
  
new_contents: var Fabric = require('fabric').fabric || fabric;
  var mixin = require('./mixin');
  
  var Arrow = Fabric.util.createClass(require('./shape_line').klass, {
     type: 'arrow',
     shapeName: 'arrow',
  
     _stroke: function(ctx) {
        var angle = this._getAngle();
        var rad = this._getLength();
        var canvasSize = this._canvasSize();
  
        var size = Math.min(canvasSize / 20, (rad / 10) + canvasSize / 80);
        var headWidthRadians = Math.PI / 6;
        var x  = Math.cos(angle - headWidthRadians) * size;
        var y  = Math.sin(angle - headWidthRadians) * size;
        var x2 = Math.cos(angle + headWidthRadians) * size;
        var y2 = Math.sin(angle + headWidthRadians) * size;
        ctx.translate(-this._getDeltaX() / 2, -this._getDeltaY() / 2);
        ctx.moveTo(x, y);
        ctx.lineTo(0, 0);
        ctx.lineTo(x2, y2);
  
        this.callSuper('_stroke', ctx);
     }
  });
  
  module.exports.klass = Arrow;
  
subject: Fix spacing [Minor]