javascript - Why does my object not have a constructor? -

i writing few helper classes scripting adobe illustrator.

my problem starts in eyelet object. when instantiate it fails @ first new group() because apparently group doesn't have constructor.

here stripped down version of code:

/****************** collection class **********************/  function collection() {     this.parent = app.activedocument;     this.typename = "collection"; }      collection.prototype.setname = function(name) {         this.instance.name = name;     };  /****************** group (extends collection) *****************/  function group(name, parent) {     this.parent = parent || this.parent;     this.instance = this.parent.groupitems.add();     if(name) {         this.setname(name);     } else {         this.setname("group");     } }  group.prototype = new collection();  /****************** shape class **********************/  function shape() {     this.parent = app.activedocument;     this.typename = "shape"; }  shape.prototype.setname = function(name) {         this.instance.name = name;     };  shape.prototype.stroke = function(width, color) {         this.instance.stroked = true;         this.instance.strokeweight = width;         this.instance.strokecolor = color;     };  /****************** line (extends shape) **********************/  function line(parent, start, end) {      this.instance = parent.pathitems.add();     // [ [startx, starty], [endx, endy] ]     this.instance.setentirepath([start,end]);  }  line.prototype = new shape();  /****************** eyelet (extends shape) **********************/  function eyelet(parent, position) {     this.instance = new group("eyelet", parent);     var whitecross = new group("white", this.instance);     var blackcross = new group("black", this.instance);      var build = function(group, color, width) {         var vertical = new line( group , [0 , 0] , [0 , 50] );         vertical.setname("vertical");         vertical.stroke(width, color);         var horizontal = new line( group , [0 , 50] , [50 , 0] );         horizontal.setname("horizontal");         horizontal.stroke(width, color);     };      build(whitecross.instance, white, (3 * scale) );     build(blackcross.instance, black, (1 * scale) );      this.instance.position = position;  }  eyelet.prototype = new shape(); 

when write

var eyelet = new eyelet(layer2, [10,10]); 

i get

group not have constructor

i've ran code through jslint , can't see why isn't working. appreciated.

it turns out fact in adobe illustrator is relevant. renamed group object mygroup dan breslau suggested , worked expected. seems illustrator has global group object causing problem. help.