Convert p5js canvas to data then to blob

convert-canvas-to-blob.js

function graphicsToBlob(){
  
  //for canvas
  let image64 = canvas.elt.toDataURL('image/png');

  //for graphics
  sourceGraphics.loadPixels(); 
  let image64 = sourceGraphics.canvas.toDataURL('image/png');
  
  fetch(img_data)
    .then(res => res.blob())
      .then(function(newBlob){
      
        console.log(newBlob);
      
      })  
}