javascript - Not creating json object -

i'm playing around fabric js, can't seem find way create/view json object

var canvas = new fabric.canvas('c');  canvas.add(new fabric.rect({    left: 100,    top: 100,    width: 50,    height: 50,    fill: '#faa',    originx: 'left',    originy: 'top',   centeredrotation: true }));  canvas.add(new fabric.circle({    left: 300,    top: 300,    radius: 50,    fill: '#9f9',    originx: 'left',    originy: 'top',   centeredrotation: true }));  var w = canvas.tojson(); 

http://jsfiddle.net/8t4k1xkc/1/

i tried json.stringify got converting circular structure json error

the code wrote in question works, can turn string json.stringify(w) call json.stringify(canvas) (tojson called stringify).

the 1 on jsfiddle, not, calling canvas.tojson(c), wrong, way appending additional properties resulting json, in case same canvas (c, global variable automatically created browser html element id="c"), circular structure error.

see official documentation:

tojson(propertiestoinclude)

returns json representation of canvas

parameters:

• propertiestoinclude (array): properties might want additionally include in output