🛠 add type property to all primitives

js/anchor.js

···
 };
   
 Anchor.prototype.toJSON = function () {
-  var result = {};
-  var optionKeys = this.constructor.optionKeys;
+  var type = this.type;
+  var ignoreChildren = this.ignoreChildren || false;
+  var result = { type: type };
+  var optionKeys = [...this.constructor.optionKeys];
 
-  [...optionKeys, 'children'].forEach(function (key) {
+  if (!ignoreChildren) {
+    optionKeys = [...optionKeys, 'children'];
+  }
+
+  optionKeys.forEach(function ( key ) {
     if (['addTo', 'dragRotate', 'element', 'resize'].includes(key)) return;
     var value = this[key];
     var defaults = this.constructor.defaults;

js/box.js

···
 // ----- BoxRect ----- //
 
 var BoxRect = Rect.subclass();
+
 // prevent double-creation in parent.copyGraph()
 // only create in Box.create()
-BoxRect.prototype.copyGraph = function() {};
+BoxRect.prototype.copyGraph = function () { };
 
 // ----- Box ----- //
 
···
 delete boxDefaults.path;
 
 var Box = Anchor.subclass( boxDefaults );
+Box.prototype.type = 'Box';
+Box.prototype.ignoreChildren = true;
 
 var TAU = utils.TAU;
 

js/cone.js

···
   length: 1,
   fill: true,
 });
+  
+Cone.prototype.type = 'Cone';
 
 var TAU = utils.TAU;
 

js/cylinder.js

···
   color: '#333',
   updateSort: true,
 });
+  
+CylinderGroup.prototype.type = 'CylinderGroup';
 
 CylinderGroup.prototype.create = function() {
   Group.prototype.create.apply( this, arguments );
···
   frontFace: undefined,
   fill: true,
 });
+  
+Cylinder.prototype.type = 'Cylinder';
+
 
 var TAU = utils.TAU;
 

js/ellipse.js

···
   quarters: 4,
   closed: false,
 });
+  
+Ellipse.prototype.type = 'Ellipse';
 
 Ellipse.prototype.setPath = function() {
   var width = this.width != undefined ? this.width : this.diameter;

js/group.js

···
   updateSort: false,
   visible: true,
 });
+  
+Group.prototype.type = 'Group';
+
 
 // ----- update ----- //
 

js/hemisphere.js

···
 var Hemisphere = Ellipse.subclass({
   fill: true,
 });
+  
+Hemisphere.prototype.type = 'Hemisphere';
 
 var TAU = utils.TAU;
 

js/illustration.js

···
   onDragEnd: noop,
   onResize: noop,
 });
+  
+Illustration.prototype.type = 'Illustration';
 
 utils.extend( Illustration.prototype, Dragger.prototype );
 

js/polygon.js

···
   sides: 3,
   radius: 0.5,
 });
+  
+Polygon.prototype.type = 'Polygon';
 
 var TAU = utils.TAU;
 

js/rect.js

···
   width: 1,
   height: 1,
 });
+  
+Rect.prototype.type = 'Rect';
 
 Rect.prototype.setPath = function() {
   var x = this.width / 2;

js/rounded-rect.js

···
   cornerRadius: 0.25,
   closed: false,
 });
+  
+RoundedRect.prototype.type = 'RoundedRect';
 
 RoundedRect.prototype.setPath = function() {
   /* eslint

js/shape.js

···
   backface: true,
 });
 
+Shape.prototype.type = 'Shape';
+
 Shape.prototype.create = function( options ) {
   Anchor.prototype.create.call( this, options );
   this.updatePath();