json.stringify: After resizing of an object height and width properties are not updated

Next code create triangles on canvas, if you are not clicking over an existing triangle. And you may save all elements to JSON with clicking on "save" button.Then preview the JSON variable in console.

My problem is that after resizing of an object, height and width are not updated in Json when clicked on save again.

What action must I perform to have also new height and width of the object?

 //HTML
    <input type="button"class="Btn1" id="saveJsonID" value="Save"/></br><br>
    <canvas  id="c5" width="1060" height="550"   style="border: 1px solid black"></canvas>

    //JS
     var canvas = new fabric.Canvas('c5');
      
function some1(x1,y2){
           var c = new fabric.Triangle({
              left: posX2,
              top: posY2,
              width:15, 
              height:25,
              strokeWidth:3,
              fill:'#666',
              stroke: '#666'   
            });
         canvas.add(c);
        }
        
 var  posX2 , posY2 ;
  canvas.on('mouse:down', function(e) {
        var circle1=[];
           var pointer = canvas.getPointer(e.e);
                posX2 = pointer.x;
                 posY2 = pointer.y;
              if (e.target){}else{some1(posY2,posY2);}
          });

function saveJsonF(){ 
        var jsonToPHP= JSON.stringify(canvas.toObject());
        console.log(jsonToPHP);
        }
  document.getElementById("saveJsonID").onclick = saveJsonF;

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