JSFiddle - React, Tailwind, and code Playground

HTML

<canvas id='canvas'></canvas>
<a id='a'>click me to save</a>

JavaScript

$('#a').click(save);

function save(ev){
  $('#canvas')[0].toBlob((blob)=>{
    let URLObj = window.URL || window.webkitURL;
    ev.target.href = URLObj.createObjectURL(blob)
    ev.target.download = "untitled.png";
  });
}